Theses medicae de divina et admiranda hominis in utero formatione

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I.
IT has been granted by Nature to all things that they not only endeavor to hold the state in which they are placed for the longest possible time, but also always to return themselves to a better one. For all desire to approach as closely as they can to the nature of the supreme and most perfect Being, and to become in some way participants of His divinity.

II.
Although all are held by this desire for perpetuity and perfection, they cannot arrive at the state which they crave due to the impurity and weakness of the matter in which they are immersed. Therefore, as many as consist of this matter have the cause of their destruction innate within them, and they necessarily perish at a certain time.

III.
Animals themselves, being more excellent than the rest, endeavor to ward off this destruction from themselves more than others, and to defend themselves from it through the propagation of their species, which they could not do through the preservation of the individuals, and to transfer themselves into some state of immortality.

IIII.
Hence Nature has implanted in individuals the desire for generating and producing something similar to themselves, and has also established the first principles of procreation, of which one should obtain the rationale of form and the efficient cause, and the other, however, the rationale of matter.

V.
But these are the Male and the Female: the sex of which in plants, which are occupied only by natural functions and cannot move from their place, is confused; in animals, however, which are endowed with both sense and motion, it is distinct, and most especially in man, who, being a participant of reason, was fashioned for other more excellent functions.

VI.
These principles of procreation are distinct, both by a certain faculty and also by the specific parts which serve procreation. For the Male can generate only in another, but the female can [generate] within herself. Furthermore, the Male can perfectly cook his own nourishment, but the Female cannot.