On Generation

​6. This is also the case: sometimes that which is released from the woman is stronger, and sometimes weaker; and that from the man likewise. Both female and male seed exist in the man, and likewise in the woman; and the male is stronger than the female, for it is necessary that [the male] arises from stronger seed. And this is also the case: if on the one hand the stronger seed comes from both, a male is produced; but if weak, a female. Whichever of the two prevails in quantity, that is what is produced; for if the weak seed is much more than the stronger, the stronger is mastered and, being mixed with the weak, is turned into a female; but if the stronger is more than the weak, and the weak is mastered, it is turned into a male. It is just as if someone, having mixed wax and fat together, having made the fat more, should melt them on the fire: as long as it is liquid, that which prevails is not apparent; but when it solidifies, then it becomes clear that the fat prevails over the wax in quantity; so it is also with the male and female seed.

​7. What happens in manifest cases allows us to infer that both in the woman and in the man there is both female and male seed. For many women have already borne daughters with their own husbands, but going to other men, they bore sons; and those same men with whom the women bore daughters, having come to intercourse with other women, begot male offspring, and those for whom male offspring was produced, having mixed with other women, begot female offspring. This argument shows that both the man and the woman have both female and male seed; for with those with whom they bore daughters, the stronger was mastered, since the weak became more, and females were produced; but with those with whom they bore sons, the stronger prevailed, and males were produced. And this [seed] does not always go out strong from the same man, nor always weak, but different at different times. And it is the same with the woman, so that one should not wonder that the same women and the same men produce both male and female offspring. It is also the case with beasts regarding the female and male seed.

​8. And in the seed itself, it goes out from both the woman and the man from the whole body, weak [seed] from the weak parts and strong [seed] from the strong parts; and it is necessary for this to be transmitted to the child. From whichever part of the man’s body more [seed] comes into the semen than from the woman’s, that part resembles the father more closely; and from whichever part more comes from the woman’s body, that part resembles the mother more closely. And it is not possible to resemble the mother in everything and the father in nothing, or the opposite of this, nor to resemble neither in anything; but there is some necessity to resemble both in some respect, if indeed the seed goes from both bodies into the child. Whichever of the two contributes more to the resemblance and from more parts of the body, to that one the child resembles in more respects; and sometimes a daughter, being born, resembles the father more closely in most respects than the mother, and a son, being born, sometimes resembles the mother more closely than the father. And these and so many things are proofs for my previous argument, that there is both male-producing and female-producing seed both in the woman and in the man.