1. Introduction
How are humans born? How is a new baby conceived and brought into the world? Human generation and embryology have long been critical in the context of medieval and modern philosophy and theology or science. However, it is only relatively recently that the academic field has started to recognize the close relations between the religious/philosophical and scientific/medical understandings of human generation, not as antitheses or rivals but as collaborators or parallel streams of thought. Embryology presents an important part of the understanding of how human beings conceive and reproduce, one that brings together different intellectual fields (Chung, 2019: 240–241). This study has historically been deeply connected to philosophical and spiritual frameworks, extending beyond the boundaries of medical science (Neaves, 2017: 2541). Such aspects are often neglected in contemporary discourse on evolutionary embryology.
On the other hand, when women’s roles in the history of medicine, especially in gynecology, started to be investigated in the late twentieth century, scholars discovered that women engaged in producing medical knowledge as well.1) In particular, the German nun Hildegard of Bingen (1098–1179), whose medical work was often described as isolated or disconnected from the majority of the medical theories of her time, began to be newly appreciated as someone who was actively engaged with not only theological but also medical theories.
Although Hildegard of Bingen and other women have begun to receive recognition in the history of medicine, this attention has often been narrowly focused on their contributions to gynecology rather than embryology. While gynecology is undoubtedly important for health and life, the works of these women were often dismissed as mere practical manuals lacking engagement with more philosophical or theoretical debates, such as those surrounding embryology. Since Monica Green first investigated women’s substantial contribution to medieval gynecology, scholarship has expanded to explore women’s roles in science and medicine more broadly (Green, 2008). However, their contributions to embryology remain underexamined, particularly in relation to the theoretical dimensions of medicine and science.
Hildegard of Bingen, for example, was an active participant in the medieval peak of Western medicine, a period marked by the transmission and reinterpretation of ancient and Arabic embryological theories by Western scholars. Yet, the history of embryology often overlooks the contributions of women, a marginalization exacerbated by the rise of male authority in gynecology through licensing systems and male-dominated guilds from the twelfth century onward (Green, 2008). This marginalization is exemplified by Franklin Needham’s A History of Embryology (1959), a foundational work in the field, which rarely mentions women apart from Hildegard of Bingen. Even within this limited acknowledgment, Hildegard’s contributions are relegated to a section subtitled ‘Visions,’ while male theorists like Albertus Magnus are afforded entire chapters on their scientific contributions (Needham, 1959: 84–86).2) Such framing underscores the need for greater academic attention to women’s contributions to embryology as part of the broader theoretical history of medicine and science.
2. Hildegard of Bingen and the Foundations of Medieval Embryology
Hildegard of Bingen (1098–1179) was a German Benedictine nun who was a prolific writer, uncommon for women of her period. She was known to receive visions from God, who was the source of her knowledge according to her and her followers. Although Hildegard referred to herself as simple and “uneducated” in her books and letters, she must have received a certain level of education. She read her contemporaries’ books and composed spiritual and scholarly works. Along with her famous books of visions such as Scivias, she composed two books on natural science and medicine, Physica and Cause et cure, while her understanding of the human body is also present in her writings in other fields, such as music and drama, where she highlights women’s important roles in God’s creation and salvation.
Hildegard should not be the only woman in embryology; however, except for her manuscripts, it is hard to find a surviving book wholly devoted to medicine that has been historically proven to have been written by a woman. At the same time, among women and men, it is hard to find another theologian whose expertise reached to embryology. Recent feminist scholars, such as Monica Green and Victoria Sweet, have started to appreciate Hildegard’s knowledge of human generation (Green, 2008; Sweet, 2006). As they argue, Hildegard of Bingen established herself in the history of science by reading translations of classical medical and philosophical knowledge and the medical and philosophical works of her contemporaries. Hildegard was familiar with the most up-to-date medical and theological theories of her time, and she was at the center of the historical debates although she was not entirely free from the conventional physiology that men were stronger, and women were weaker.
Hildegard’s medical and scientific perspectives require further examination through the lens of embryology, as scholarship has predominantly focused on her contributions to gynecology and medical practice. She synthesizes embryological understanding through an interdisciplinary lens, integrating contemporary physiological theories, classical medical knowledge, and Christian theological perspectives into a comprehensive natural philosophical framework. Limiting Hildegard to gynecology, largely due to her being female, is to limit her vast knowledge of human generation to diagnoses and treatments, not appreciating her foundational concepts of human origins and generation along with her ideas of pathology. And even further, Hildegard’s writings suggest that women were not simply practicing midwifery but were also developing their own version of embryology as foundational knowledge.
For Hildegard, just as for Aristotle, Galen, and Albertus, it is necessary to understand how humans are generated to understand what is needed to help their generation and improve their reproductive health. And as those male theorists all did, Hildegard also combined her theology and embryology to link human origins and ends. In particular, her semen theory, even if not fully discussed as a separate topic, represents her deep understanding of the human condition in the close connections with natural science and the religious background that her theory shares with those of male embryologists. Hildegard stands out among female medical experts, and even among most male scholars, for her ability to develop and elaborate embryological knowledge during the Middle Ages.3)
Hildegard’s Cause et cure, her medical book composed in the twelfth century, devotes a significant part of the earlier chapters to human generation. Unlike her spiritual books, Hildegard of Bingen’s Cause et cure gained scholarly attention in the mid-20th century amid debates over its authorship. Now widely attributed to her, the text exemplifies her distinctive integration of medical knowledge, natural philosophy, and spiritual insight. Her contributions to humoral theory, practical medicine, and the synthesis of diverse healing traditions establish her as a pivotal figure in medieval medical history.
The book begins with the origin of the universe to contextualize the emergence of the first human beings. According to Hildegard’s views of the microcosm and macrocosm, which show her desire to encompass the logic applied to every creature, the human being’s symptoms can be understood and treatments identified only through understanding God’s creation. She begins directly from the creation of the world, giving an account aligned with Genesis in the Hebrew Scripture.4)
In Cause et cure, the creation of the world is followed by the creation of the angels, the fall of Lucifer, and the creation of all other natural objects and phenomena in Book I. Book II starts with the fall of Adam, which is the main reason why humankind has a need for reproduction after becoming mortal. Book II makes up the largest part of Cause et cure, covering various topics in the microcosm and the macrocosm, from animals to diseases. The chapters of Books III, IV, and V discuss various diseases and bodily symptoms. And Book VI explains conception in relation to astronomy. Across her various medical treatises, however, the topic that Hildegard returned to most frequently was human reproduction. For her, diseases and reproduction shared the same cause: the original sin of the first humans disturbed the perfect condition of the body and mind. Therefore, the solution was the same, to find the right balance between humors and elements in the body, returning to the prelapsarian state.
Therefore, Hildegard repeatedly returned to the foundational question of how human beings were created and what their creation would reveal about the current human state, including reproduction. Hildegard’s semen theory was the product of combining her knowledge of classical embryology and medieval theology with her unique appreciation of the woman’s sexual/reproductive body. Rather than the gender hierarchy of the Aristotelian and Galenic theories, this female saint emphasized the complementary roles of both sexes, which were also represented in her understanding of seed.
Examining Hildegard of Bingen’s embryology is valuable not simply because she provides a rare case of female perspective. Possibly grounded on her experience as a woman witnessing other women’s engagement with and refusal of reproductive/sexual life, she developed a unique embryology not dependent on the man’s semen. Rather, she saw the importance of uiriditas, the greening power existing in women, and appreciated complementary roles in generation by both sexes.5) Her new embryological theory solved the dilemma perpetually posed by the earlier embryologies of Aristotle and Galen, which highlighted the dominance of the man’s semen while failing to explain the woman’s contribution to human generation.
Granted that it is not so uncommon to find the microcosm and macrocosm in the Middle Ages,6) Hildegard of Bingen’s medical-theological writings take a particular place in the history of medicine. She combined ancient Greco-Roman medical theory, the medieval Christian story of creation and salvation, and German folk medicine. At the same time, unlike male theologians and medical theorists, Hildegard dared to represent the positive dimensions and meanings of the female body.7) Hildegard did not do this simply because she was a woman, but it is related to the fact that she was a woman, more particularly a female theologian8) and medical expert.
Her medical book, Cause et cure, is a collaboration between her theology and medicine. For Hildegard, how human beings were created by God and how they could maintain their bodies and souls in health could not be separated but were interconnected. If we want to understand why human beings fall into sickness, it is necessary to acknowledge how God created human beings and how human beings degenerated due to original sin. Her embryological theories significantly contributed to her broader medical framework, particularly in understanding the human condition. However, as previously noted, they have not been afforded serious consideration within the history of embryology, despite her broader recognition in the fields of general medicine and gynecology. Scholarly interest in Hildegard of Bingen’s medicine has revived since the full manuscript of Cause et cure was rediscovered and her contribution was re-evaluated in the middle of the twentieth century as a woman specialized in physiology and natural science as well as theology.
3. Aristotle’s One-Seed Theory
To emphasize the gender-complementary aspects of Hildegard’s embryology, it is essential to contextualize her work within the dominant embryological theories of her time. Medieval embryology was largely divided into Aristotelian and Galenic theories, which disagreed on the number of seeds (Connell, 2000: 406). While Galen was frequently referred to as an authoritative figure in medieval medical and scientific manuscripts in the Middle Ages (Jacquart & Thomasset, 1988: 48), Aristotle’s embryology became influential mostly through the Arabic translations that introduced ancient theories on this topic to Europe. Aristotle (384–322 BCE), who contributed to building the Western history of medicine and medical theory, claimed in his one-seed theory that it was only men who contained seed or semen.9) For him, semen did not simply make conception possible but also had the power to generate human beings. On the other hand, women, who did not have seed, only provided the fetus with material, because they lacked semen and generative power. In this hylomorphism, according to which matter and form in unity constitute the material object (Marmodoro 2013: 5), the man’s body provided the form for a baby, and the woman’s body only provided the matter. In his famous Generation of Animals, Aristotle clearly stated that women did not have semen.
Now since what comes to be from females is as the semen from males, and it is not possible for two spermatic secretions to come to be at once, it is plain that the female does not contribute semen to generation. For if (the female) had semen, it would not have menstrual fluid. Now because that one is present [in the female], the other one (semen) is not (Aristotle, 1910: I, 19, 727a26–30).
Instead of semen, Aristotle argued that women had menstrual blood, which might contribute to conception by providing materials. In this one-seed theory, the woman’s menstrual blood and the man’s semen are coagulated to bring about conception. However, this menstrual blood lacks the same generative power as the man’s semen, although it can at least fertilize eggs and feed embryos.
This understanding that only the seed contained the generative power, the more fundamental ability to generate a new human being, and that this semen was only possessed by men placed the male in the more active role in reproduction.
But the female, as female, is passive, and the male, as male, is active, and the principle of the movement comes from him. . . . It is plain then that it is not necessary that anything at all should come away from the male, and if anything does come away it does not follow that this gives rise to the embryo as being in the embryo, but only as that which imparts the motion and as the form; . . . . (Aristotle, 1910: I, 21, 729b10–20).
On the other hand, women were ascribed a passive role in reproduction, although this Aristotelian theory failed to explain why children resemble their mothers, too.10) Aristotle’s successors embraced the possibility that women might produce semen-like substances, but they still kept Aristotle’s stance that women did not contribute to the formation of the embryo. In other words, they maintained the view that a woman’s menses provided the material for the fetus, while the man’s semen imparted its essential form (Jacquart & Thomasset, 1988: 64–65). Therefore, even if women had a semen-like liquid, it was not comparable to the man’s sperm.
This is more obvious in Aristotle’s use of the cheese analogy in his embryology,11) which Hildegard of Bingen later adapted in a way that more explicitly acknowledged women’s contributions. Evidently, Aristotle saw semen as having the more fundamental power to form a fetus. The man’s semen is compared to rennet in milk, which initiates coagulation to make cheese. Rennet and the semen had “vital heat.” The milk is the matter that is acted upon, like catamenia or the woman’s menstrual fluids. While both are certainly needed for making cheese, the seed has the fundamental power to form and impart movement to the embryo by separating liquid and solidified materials; the latter becomes the fetus.12) The roles of men’s and women’s sexual fluids were distinct in Aristotelian theory. The woman’s fluid was more passive, while the man’s was more active. Elsewhere, Aristotle once again emphasized the vitality of semen, which menstrual blood did not have.13) Because women “lacked” semen, they did not need to ejaculate for conception; therefore, sexual pleasure was not required for women, unlike men. Although the Aristotelian one-seed theory was not accepted as widely as the Galenic two-seed theory, it certainly had a significant impact on the philosophical and gynecological fields. Hildegard’s embryology aligns with the Aristotelian one-seed model of human generation, yet she emphasizes maternal contributions by elaborating on fertilization, pregnancy, and childbirth processes.
4. Galen’s Two-Seed Theory
Galenic theory, which did not agree with the Aristotelian one-seed theory, allowed a female seed to women. Galen (129–216 CE) agreed with Aristotle that semen had the generative power that was essential to make an embryo. Unlike Aristotle, however, Galen argued that women had semen like men.
Now the fact that the female animal has semen must be accepted on the evidence of the senses, as we said earlier, and the existence of what is clearly seen must not be overturned by argument. But we must try to find the reason why, when the female too produces semen, the male animal nevertheless came into being, or why, when the male had come into being, the female’s semen was also preserved; for it was better for it to have a residue that contributed to the generation of the fetus (Galen, 1992: I, 11, 5–7).
When Galen was developing his two-seed theory, he clearly acknowledged the Aristotelian theory of one seed, and he based his opposition to it on his observation and evidence. However, this does not mean that Galen appreciated the woman’s equal contribution to conception. For him, the woman’s semen could not be equivalent to the man’s. The woman’s semen was weaker and less complete compared to the man’s (Chung, 2019: 245).
Why do women have weaker semen? According to Galen, it was because the woman’s body was colder and wetter than the man’s body: “because the female is colder in krasis14) than the male” (Galen, 2020: II, 606K, 153).15) The fact that women tend to have more fat also supported his hypothesis; Galen said that fat was more strongly associated with colder animals.16) This claim was able to be supported by the role of humors in gender differences. Women, having more fat, possessed the colder body and humors, based on humoral composition. Galenic humoralism considers the four different humors as essential to the human body, blood, (yellow) bile, black bile, and phlegm, which should be balanced to keep one’s health sound. And these humors have different characteristics in terms of hot/cold and dry/wet qualities. According to this humoralism, the woman’s body lacked heat, which was considered the better quality. Therefore men, whose bodies were believed to contain stronger heat, could produce better semen that contributed more to conception.
Again, at the same time, it was obvious to Galen that women did not have the same qualities in their semen as men do: “[w]ell, then, Aristotle was right in thinking the female less perfect than the male” (Galen, 1968: 14, II, 296, 5). Since women were colder, their bodies were inferior (Galen, 1968: 14, II, 296, 6), and they failed to produce semen of the same quality: “the semen generated in them [female testes] must be scantier, colder, and wetter” (Galen, 1968: 14, II, 301, 6). Like Aristotle, Galen saw making semen as a process of concoction that required heat. Since women lacked heat, their semen was no better than the prostatic liquid (Jacquart & Thomasset, 1988: 62).
Interestingly, Galen’s theory posited that ejaculation was necessary for both men and women, asserting that fertilization occurred only through the combination of two ejaculated seeds. Unlike the Aristotelian theory, which dismissed female ejaculation due to the belief that women lacked semen, Galen emphasized the importance of female ejaculation and the role of pleasure in triggering it.17) Also, Galen considered the female pleasure from intercourse to be evidence of the female seed (Galen, 1992: 175, 2.4, 13).18) However, even for him, female sperm played more of a supporting role, not that of the main contributor like male seed.
On the other hand, at the anatomical level, Galen claimed to observe that women had testicles like men to produce semen—his interpretation of the ovaries in modern science—and their fallopian tubes might become empty after coitus (Galen, 1992: 145, 2.1, 2–6). The difference was that women would ejaculate inside their uterus while men would do so outside their genitals.
Nevertheless, that woman’s genitals were inside the body supported Galen’s belief in female inferiority. He saw the woman’s body as not as complete as the man’s, on the grounds that women had their genitals inside while the man’s came out externally by pneuma (Galen 1992: 191-92, 2.5, 52–60). Here, Galen’s famous analogy of the mole’s eyes appeared to explain the imperfect status of women’s genitals.
If ever it should lack the strength for the final act, it leaves unfinished the thing being made, as is seen, for instance, in the whole race of moles; their eyes were sketched internally but were unable to emerge to the outside, their nature having lost the strength for this, so that it did not complete the work it had proposed to do (Galen, 1992: 193, 2.5, 60).
Like Aristotle, Galen also observed that the main role of the woman’s sexual body was to provide a fetus with matter, such as nourishment, and a place (Connell, 2000: 419), which was rather similar to the Aristotelian embryology.
It was Galen’s two-seed theory which was more widely adopted in medieval medicine (Jacquart & Thomasset, 1988: 62), although interestingly, Hildegard of Bingen’s theory has more similarities to the Aristotelian one-seed theory, as will be discussed in the next section. Greatly influenced by Galen, medieval embryology continued to uphold the supportive position of the woman’s semen. For example, ‘Ali ibn al-’Abbās (d. 994), highly influenced by Galen, asserted that female semen was useful and necessary because it would liquify and decrease in thermal intensity so that the man’s thick, heated semen could spread and reach the woman’s womb. Although woman’s seed was “useful,” it was still believed by many medieval male theorists that the woman’s sexual fluid performed a secondary role. The woman’s seed was believed to contribute its thinness and frigidity—qualities typically regarded as inferior to thickness and heat—along with nourishment to the fetus.
Whether or not women could produce semen or could contribute to giving generative power to the man’s semen, both theories shared the commonality that the woman’s sexual fluid was inferior to the man’s. Both were substantially based on the gender theory that men’s bodies possessed better qualities, and therefore, their contribution to reproduction had to be more crucial. Whether women were believed to produce semen or not, the focus was whether women would provide substantial qualities to the fetus. And in either case, the woman’s reproductive role was considered passive in contrast to the man’s active role, as well as supplementary to the man’s essential part,19) highlights Hildegard’s distinctive emphasis on the woman’s agency both before and after fertilization.
5. Hildegard of Bingen’s Embryology
5.1. The Hildegardian One Seed Theory in Medicine: Women’s Primary Contribution to Generation
One of the most debated topics that Hildegard of Bingen engaged with throughout her lifetime was embryological theory. Hildegard must have known the classical views about semen, along with other theories that she was exposed to. Her semen theories, like the Greco-Roman ones, appear in her discussion of conception. Her medical book, Cause et cure, plays a significant part in explaining how human beings are conceived. However, how she might have contributed to the general history of medicine had often been often neglected, and she has often been described as isolated from the major medical discourses of her time. However, recent studies have depicted her as at the center of medical discussion and theories, influencing the formation of medical knowledge in the Middle Ages.20)
Hildegard’s theory of semen was similar to Aristotle’s one-seed theory in that she did not find semen in the woman’s body.
Because man’s flesh was made from earth, his blood has semen of a strong and correct nature. A woman’s blood is also of a correct nature. Because she is weak and tender she does not have semen, but emits merely a tiny, watery foam, since she is not of both earth and flesh, as a male, but was taken only from the flesh of the male (Hildegard of Bingen. 2008: 51).21)
Unlike Aristotle, Hildegard of Bingen did not see the generative power of the form only in male semen. As noted above, the Aristotelian one-seed theory failed to explain why children could resemble their mothers. Although Hildegard technically supported the one-seed theory, she did not confine generative power solely to the man’s seed. Rather, she asserted that women made a significant contribution to conception, which accounts for the variation in forms and resemblances among offspring. For example, she saw different dynamic processes and different results shaping the fetus and baby, such as when the woman’s heat “overcomes the semen of man, so that the child is often formed with their appearance (Hildegard of Bingen, 2008: 30).”
Strictly speaking, Hildegard argued for a one-seed theory, in which only men contain and ejaculate semen. However, upon closer examination of her theory, it becomes clear that she did not emphasize the absence of semen in women. Whether or not women could produce semen was not the focus in her embryology. Even if women lacked semen, they were fully needed to bring a new life into the world. Hildegard highlighted the woman’s role in conception by identifying various bodily elements, including female foam, as equal contributors to reproduction.
For instance, Hildegard highly valued the woman’s ability to nullify the toxic nature of the man’s semen. In order to enable reproduction, humans needed the fact that women did not have semen, because men’s semen had degenerated so much that men’s bodies were not capable of making new life. For Hildegard, the human reproductive process is a smaller version of God’s creation. This process involves the four basic elements, fire, earth, water, and air, just like God’s creation. God sends the soul into the fetus so that the fetus could be divided and develop into a human form. And finally, the baby comes out of the mother’s body just like Eve was created from Adam’s body by God’s eternal power.22) If human generation was the repetition of God’s creation of the first human beings, it had to be free from conditions directly related to any defects, especially original sin. Semen was impacted by Adam’s transgression,23) but this degenerate seed did not exist in the woman’s body, giving hope to human generation because the woman’s body was deprived of semen.
Then, why did women not have semen, and why and how were they less impacted by the aftermath of the original transgression? Again, Hildegard’s embryology looks all the way back to God’s creation, underlining the close relationship between her theology and medical theory. When God created the first human beings, God used different materials to make them. Adam’s creation came straight from the natural elements in the form of mud.24) In contrast, Eve was created from Adam’s flesh, which gave her distinctive features such as softness and malleability.25) Traditionally in Christian theology and medicine, these female characteristics were often translated into the weakness and inferiority of women. However, Hildegard replaced these womanly defects with strengths, which must have been useful to her in claiming distinctive authority as God’s female messenger.
According to Hildegard of Bingen, at the same time, the different creations of Adam and Eve differentiated the first couple’s reproductive bodies. As noted above, she argued that women did not have semen as men did. Adam ended up having semen because he was directly produced from earth, which is characteristically strong and rigid. Therefore, Adam’s body and mind were already strong and rigid from the moment of his creation, and his condition, which would be inherited by his male descendants, gave him semen.
On the other hand, Eve, created out of her partner’s flesh, is as soft in her mind and body as his flesh, resulting in a semen-free condition that would be inherited by her female descendants as well. Nevertheless, this does not mean that Eve lacked a reproductive role in conception. Hildegard claimed that women’s foam contributed to making an embryo.26) The woman’s foam is something closer to our understanding of an egg. This “foam” was not as thick as semen, but it was certainly essential to bring a new life into the world.
In addition, Hildegard’s embryology addresses the defective nature of semen, which is not found in the male ancient philosophers. For Hildegard, semen became deformed when Adam committed sin, which caused degeneration of his body and mind, and most importantly his semen. Eve, despite committing the sin first, could avoid the degeneration of semen because she did not have semen in any case. Adam’s body received the direct impact of sin due to its strength, unlike Eve’s soft and malleable body. Instead, Eve started to have flows, meaning menstruation. “In Adam’s transgression, the strength in the male’s genital member changed into a poisonous foam, and the female’s blood changed to a dangerous effusion” (Hildegard of Bingen, 2008: 51). Her “weak and fragile” body saved her from the poison of original sin.
God created the human being, and all animals were subject to serving him; but when man transgressed God’s order, he was changed in mind and body. The purity of his blood changed to another type, so that instead of purity, it throws off the foam of semen. If the human had stayed in paradise, he would have continued in his unchangeable and perfect state. But these all changed after the transgression into another, bitter type (Hildegard of Bingen, 2008: 28).27)
It was Adam’s semen that degenerated so much that human beings began to suffer disease and death. Now, the woman’s foam had to perform its reproductive duty by overcoming the man’s noxious semen.28)
Therefore, Hildegard notes that sexual pleasure is necessary for conception, as it enables the couple to emit sexual fluids, the foam from women and semen from men,29) similar to the Galenic two-seed theory to some extent. The argument about whether sexual pleasure might be absolutely needed for fertilization is rather complicated in terms of the gendered contribution to reproduction.30) For Hildegard, sexual satisfaction made it possible for the couple to ejaculate the needed substances, whether it was the man’s semen or the woman’s foam. What makes her different from her predecessors or contemporaries is that she evaluated the crucial part played by affection. The nonaffective part of sexual pleasure is directly related to original sin and was given to humankind as a punitive result.
This does not mean that Hildegard of Bingen overturned the gender hierarchy: “The woman is subject to the man in that he sows his seed in her, as he works the earth to make it bear fruit” (Hildegard of Bingen, 1990: 84). However, she did not advocate its absolute fixation, either. Unlike philosophers or philosophically oriented theologians in antiquity or the Middle Ages, she was relatively unconcerned about whether women had semen or not. In the end, the ultimate power to generate came from God, not from men or women, because human reproduction is the smaller version of God’s creation.
Hildegard’s embryology did not fixate on passivity or activity in gender roles. By emphasizing the complementary roles of the two sexes, she minimized the sex/gender hierarchy. Her embryology is the scientific version of her theology that women and men could not exist without each other (Cadden, 1993: 153). Furthermore, this extends to her theological view that God and human beings could not exist without each other. In the same logic, the moon and the sun, the Church and Jesus should coexist (Hildegard of Bingen, 1990: 2.5, 202). Even if Hildegard did not argue for the woman’s seed, she still valued the woman’s pleasure, like Galen. She emphasizes the mutual love between the couple; therefore, the female’s affection toward her male partner decides how healthy the fetus is, while the man’s semen decides its sex (Hildegard of Bingen, 2003: II.63, 62–63). Also, the power of the form was not in either the male seed or the female foam. It came directly from God, one month after conception. In Cause et cure, it was the soul that would give the fetus a form. Prior to ensoulment, the fertilized egg was considered an unformed mass. Once ensoulment happened, it started to be divided into different parts and to have possibilities for movement,31) developments that are comparable to the works of the man’s semen according to Aristotle and Galen.
The major difference between Aristotle and Hildegard, despite their shared one-seed theory, is the origin of the soul. Aristotle argued that ensoulment occurs in different stages, helping the embryo to develop differently with each step, and he believed that the soul did not come from outside; rather, the soul was generated inside the embryo (Needham, 1959: 49–50). Where Aristotle saw the soul internally generated from the embryo, Hildegard understood the soul would be infused into the embryo externally, from God. Since the soul would be given by God, Hildegard did not need to locate the potential soul or form to generate the form of the fetus in the human body. Therefore, for her, the major development of the fetus did not need to come from either the man’s semen or the woman’s foam. At its most fundamental level, Hildegard did not find it necessary to address the question of the origin of the active power behind human generation.
As God’s creation was complete and free from any possible defects, human reproduction has to be free from any possible residue of original sin. Therefore, Adam’s defective semen should go through an additional process of purification, which, according to Hildegard, would happen in the woman’s body. Not having flawed semen, the woman’s body could use her blood and heat to warm the man’s semen in order to create the right conditions for conception and fertilization.
From the love of the male, her blood is aroused and she sends it, as if a foam, more bloody than white, to the semen of the male. It joins with it and shapes it, making it warm and bloody. After it has fallen into its place, and lain there, it grows cold. It is as if a poisonous foam until fire, that is heat, warms it; and until air, that is breath, dries it; and until water, that is liquid, allows pure dampness to enter; and until the earth, that is a membrane, constrains it. And then it will be bloody—not totally blood, but combined with a bit of blood (Hildegard of Bingen, 2008: 51).32)
The man’s semen needs so much care even when it is coagulated with the woman’s foam. And the process is quite similar to God’s creation, using the four basic elements. And at least in this moment, this generation is detached from original sin. Rather, the woman’s body removes the residue of original sin.
In this context, the woman’s role is undeniably significant in human generation, despite the absence of semen in the female body. In the mother’s body, the fertilized egg starts to proceed toward the shape of a human. It starts to be split and divided. Then, it begins to become a human.
5.2. The Hildegardian Seed Theory in Theology: Women’s Power of Eternity
Hildegard’s unique embryology also appears in her visions. The well-known cheese analogy for the Aristotelian theory also appears in Hildegard’s writings to explain human reproduction.
And behold! I saw on the earth people carrying milk in earthen vessels and making cheeses from it; and one part was thick, and from it strong cheeses were made; and one part was mixed with corruption, and from it bitter cheeses were formed. And I saw the image of a woman who had a perfect human form in her womb. And behold! By the secret design of the Supernal Creator that form moved with vital motion, so that a fiery globe that had no human lineaments possessed the heart of that form and touched its brain and spread itself through all its members (Hildegard of Bingen, 1990: I.4, 109).33)
This passage comes from the fourth vision of the first book of Hildegard’s Scivias, where she explains the composition of the world, including in the preceding third vision, an analysis of creation.
This part discusses the soul and body of the human being. Following her typical format, in which she first recounts her vision and then gives exegeses of it, in the next chapters Hildegard explained in God’s voice what her vision meant. This vision in general represents the human soul and how it was deceived by the devil and aided by God’s knowledge, justice, and forgiveness.
In the exegesis of this passage, God explaines to Hildegard that “the earth people” are the women and men in this world. They are holding the vessels, which are their bodies, and the cheese in the vessels designated their seeds (Hildegard of Bingen, 1990: 118). By using the analogy of cheese, Hildegard explains in God’s voice why and how people in the world vary. From thick milk, which is compared to thick semen, strong cheese is made, which “is usefully and well matured and tempered” and “produces energetic people.” These people are not just excellent in their bodies but also in their souls; therefore, they would remain strong against evil temptations.
In contrast, weak people are produced out of the weak cheese. The weak cheese is connected to weak semen, “imperfectly matured and tempered in a weak season,” which generates people who are weak and unwilling to serve God. However, according to Hildegard, the worst case is that the milk has gone bad. From the corrupted milk, bitter cheese is made. Hildegard makes extremely harsh comments about those who are born out of it. At the same time, still, there is still hope that these people can overcome their innate condition and become devout, especially when they face hardship.34) Accordingly, they are the people who can work as the messengers of God in turbulent times like Hildegard’s own period, which she calls “effeminate.”35)
For that semen is basely emitted in weakness and confusion and mixed uselessly, and it produces misshapen people, who often have bitterness, adversity and oppression of heart and are thus unable to raise their minds to higher things. Many of them nonetheless become useful; though they suffer many tempests and troubles in their hearts and in their actions, they come out victors. For if they were left in peace and quiet, they would become languid and useless, and therefore God forces them and leads them to the path of salvation (Hildegard of Bingen, 1990: 118).
This chapter is followed by a chapter referring the words of Moses, who was the spiritual leader and God’s messenger when the Israelites were suffering and then wandering in the desert, possibly because Moses could be the cheese from corrupted milk. Moses’s words also deliver the hopeful message from God that even weak people could be raised to health through his will and justice, in alignment with Hildegard’s comments on the bitter cheese people, combined with her embryology and optimistic theology.
6. Conclusion
Women have always contributed to medicine, treatment, and healing in history. While earlier studies were more focused on the nonliterary parts of women’s medical practices, the new historical approach investigates women’s written culture of medicine and actively claims that women’s contribution to the history of medicine has been dismissed by narrow studies on renowned authorities and elites. Even when women participated in academic discussions with male scholars and engaged in crafting knowledge, their academic contributions are easily overlooked.
Hildegard of Bingen was a woman whose two books on medicine and natural science have reached modern readers, representing medieval medical views on specific topics combined with folk medicine and contemporary theories. Embryology plays a significant part in her medical book, Cause et cure, as an important bridge between her theology and her gynecology. At the same time, her embryology was the academic product of the contemporary theories of her time. Her writings convey the development of embryology based on classical ancient medicine and transferred through Arabic sources. In particular, she discusses Galenic humoralism and uses the Aristotelian one-seed theory when she explains how a fetus is made in the womb.
In theoretical terms, Hildegard’s embryonic theory is closer to the Aristotelian one-seed theory than to Galen’s two-seed theory. Her discussion of menstrual fluid and her use of the cheese analogy suggest that she was likely familiar with Aristotelian embryology, either directly or indirectly. In Cause et cure, Hildegard argued that women did not generate semen like men. However, unlike the two major fathers of medicine, she emphasized the female power that the woman’s reproductive body contributed to conception, while the fetus’s form originated from God. In the Hildegardian embryology, there is no hierarchical order between the female and male fluids. For Hildegard, female foam, although it was weaker and thinner than the man’s, was not an underdeveloped version of semen.
Unfortunately, her unique appreciation for the woman’s contributions did not continue and has not been centered in other embryological theories of her time and subsequent periods. However, her embryology, along with her expertise in medicine, receives new value in light of the fact that medieval medicine was understood through Aristotle and Galen, whose embryology was highly male-centered, dismissing the woman’s role. At the same time, Hildegard’s alternative theory raises possibilities of women-empowering theories in the Middle Ages with its emphasis on the complementary roles of women and men as well as of human beings and nature. Just as Hildegardian embryology finds a way to escape male-centered views, it offers an environment-friendly way of explaining human generation, escaping human-centered views. The semen or seed cannot become the sole master key to explain the whole process of human generation. The relations and connections between different entities are the keys, as Hildegard argues.
Exploring major differences in ancient embryology, Rebecca Flemming asserts the importance of shifting our focus to understanding the nature of seeds and menstrual fluids in those theories. According to her, it is more important to analyze the woman’s sexual substance and its role than to argue whether or not women could produce seed (Flemming, 2021). Situating Hildegard of Bingen’s understanding of conception in the lively discussion of embryological traditions in premodern medicine and philosophy is important not just because it is one missing part but because it is an important case in which the woman’s reproductive contribution was more fully recognized and appreciated by a female theorist who was called a mother by her followers. Hildegard received the heritage of classical embryology and developed it into the innovative claim that the woman’s body would nourish and purify the embryo. This approach is not separable from her active role in the church when, as she claimed, the male church authorities were too tainted to fulfill their duties. As Adam’s semen suffered degeneration in its ability to contribute to reproduction as a result of his transgression, Eve’s female descendants took on an important role in human generation. Although Hildegard of Bingen did not take part in sexual or reproductive life, she also carried out an important role as a woman in putting forward an alternative theory of embryology that combined her visions with medical knowledge.