Αἴτιον δὴ τοῦ τοῖς μὲν ἄρρεσι μὴ πᾶσιν εἶναι περίττωμα γεννητικὸν τοῖς δὲ θήλεσι πᾶσιν, ὅτι τὸ ζῷον σῶμα ἔμψυχόν ἐστιν. ἀεὶ δὲ παρέχει τὸ μὲν θῆλυ τὴν ὕλην τὸ δ’ ἄρρεν τὸ δημιουργοῦν· ταύτην γὰρ αὐτῶν φαμεν ἔχειν τὴν δύναμιν ἑκάτερον, καὶ τὸ εἶναι τὸ μὲν θῆλυ τὸ δ’ ἄρρεν τοῦτο. ὥστε τὸ μὲν θῆλυ ἀναγκαῖον παρέχειν σῶμα καὶ ὄγκον, τὸ δ’ ἄρρεν οὐκ ἀναγκαῖον· οὔτε γὰρ τὰ ὄργανα ἀνάγκη ἐνυπάρχειν ἐν τοῖς γιγνομένοις οὔτε τὸ ποιοῦν. ἔστι δὲ τὸ μὲν σῶμα ἐκ τοῦ θήλεος ἡ δὲ ψυχὴ ἐκ τοῦ ἄρρενος· ἡ γὰρ ψυχὴ οὐσία σώματός τινός ἐστιν.
(Aristotle, Gen. An. 738b)
Why does this generative residue, then, not occur in all males, although it occurs in all females? The answer is that an animal is a living body, a body with a Soul in it. The female always provides the material, the male provides that which fashions the material into shape; this, in our view, is the specific characteristic of each of the sexes: that is what it means to be male or to be female. Hence, necessity requires that the female should provide the physical part, i.e., a quantity of material, but not that the male should do so, since necessity does not require that the tools should reside in the product that is being made, nor that the agent which uses them should do so. Thus the physical part, the body, comes from the female, and the Soul from the male, since the Soul is the essence of a particular body. (tr. Arthur Leslie Peck)