Yes. The semen is produced from the substance of the generator because generation is from the substance of the generator in animals and plants, inasmuch as the semen owes its power to the form of the generator, and inasmuch as it is in potentiality to the substance.
Semen est de substantia generantis quia generatio est de substantia generantis in animalibus et plantis, inquantum semen habet virtutem ex forma generantis, et inquantum est in potentia ad substantiam ipsius.
The semen is not something separated from what was before the actual whole; rather is it the whole, though potentially, having the power, derived from the soul of the generator, to produce the whole body.
Semen non sit decisum ab eo quod erat actu totum; sed magis sit in potentia totum, habens virtutem ad productionem totius corporis, derivatam an anima generantis.
Now that which is in potentiality to the whole, is that which is generated from the food, before it is transformed into the substance of the members. Therefore the semen is taken from this. In this sense the nutritive power is said to serve the generative power: because what is transformed by the nutritive power is employed as semen by the generative power.
Hoc autem quod est in potentia ad totum, est illud quod generatur ex alimento, antequam convertatur in substantiam membrorum. Et ideo ex hoc semen accipitur. Et secundum hoc, virtus nutritiva dicitur deservire generativae, quia id quod est conversum per virtutem nutritivam, accipitur a virtute generativa ut semen.
A sign of this, according to the Philosopher, is that animals of great size, which require much food, have little semen in proportion to the size of their bodies, and generated seldom; in like manner fat men, and for the same reason.
Et huius signum ponit philosophus, quod animalia magni corporis, quae indigent multo nutrimento, sunt pauci seminis secundum quantitatem sui corporis, et paucae generationis; et similiter homines pingues sunt pauci seminis, propter eandem causam.
The Philosopher proves in many ways (De Gener. Animal. i, 18) that "the semen is surplus food."
Philosophus probat multipliciter, in libro de Generat. Animal., "quod semen est superfluum alimenti".
The likeness of the generator to the generated is on account not of the matter, but of the form of the agent that generates its like. Wherefore in order for a man to be like his grandfather, there is no need that the corporeal seminal matter should have been in the grandfather; but that there be in the semen a certain power derived from the soul of the grandfather through the father.
Assimilatio generantis ad genitum non fit propter materiam, sed propter formam agentis, quod generat sibi simile. Unde non oportet ad hoc quod aliquis assimiletur avo, quod materia corporalis seminis fuerit in avo; sed quod sit in semine aliqua virtus derivata ab anima avi, mediante patre.
Kinship is not in relation to matter, but rather to the derivation of the forms.
Affinitas non attenditur secundum materiam, sed magis secundum derivationem formae.
Augustine says (Gen. ad lit. x, 20) that we were in Adam "not only by seminal formal aspect, but also in the very substance of the body."
Augustinus dicit, X super Gen. ad Litt., quod nos fuimus in Adam non solum secundum "seminalem rationem, sed etiam secundum corpulentam substantiam".
These words of Augustine are not to be understood as though the immediate seminal formal aspect, or the corporeal substance from which this individual was formed, were actually in Adam: but so that both were in Adam as in principle. For even the corporeal matter, which is supplied by the mother, and which he calls the corporeal substance, is originally derived from Adam: and likewise the active seminal power of the father, which is the immediate seminal formal aspect [in the production] of this man.
Verbum Augustini non est sic intelligendum, quasi in Adam actu fuerit aut seminalis ratio huius hominis propinqua, aut corpulenta eius substantia, sed utrumque fuit in Adam secundum originem. Nam et materia corporalis, quae ministrata est a matre, quam vocat corpulentam substantiam, derivatur originaliter ab Adam, et similiter virtus activa existens in semine patris, quae est huius hominis propinqua ratio seminalis.
But Christ is said to have been in Adam according to the "corporeal substance," not according to the seminal formal aspect. Because the matter from which His Body was formed, and which was supplied by the Virgin Mother, was derived from Adam; whereas the active power was not derived from Adam, because His Body was not formed by the seminal power of a man, but by the operation of the Holy Spirit. For "such a birth was becoming to Him" [Hymn for Vespers at Christmas; Breviary, O. P.], WHO IS ABOVE ALL GOD FOR EVER BLESSED. Amen.
Sed Christus dicitur fuisse in Adam secundum corpulentam substantiam, sed non secundum seminalem rationem. Quia materia corporis eius, quae ministrata est a matre virgine, derivata est ab Adam, sed virtus activa non est derivata ab Adam, quia corpus eius non est formatum per virtutem virilis seminis, sed operatione spiritus sancti. Talis enim partus decebat eum, qui est super omnia benedictus Deus in saecula. Amen.