Genitalia

Et cur, inquies, creata sunt genitalia, et sic a conditore sapientissimo fabricati sumus, ut mutuum nostri patiamur ardorem, et gestiamus in naturalem copulam? periclitamur responsionis verecundia, et quasi inter duos scopulos, et quasdam necessitatis et pudicitiae συμπληγάδας, hinc atque inde, vel pudoris, vel causae naufragium sustinemus. si ad proposita respondeamus, pudore suffundimur. si pudor impetrarit silentium, quasi de loco videbimur cedere, et adversario feriendi occasionem dare. melius est tamen clausis, quod dicitur, oculis Andabatarum more pugnare, quam directa spicula, clypeo non repellere veritatis. poteram quidem dicere: “quomodo posterior pars corporis et meatus per quem alvi stercora egeruntur relegatus est ab oculis, et quasi post tergum positus, ita et hic qui sub ventre est, ad digerendos humores et potus, quibus venae corporis irrigantur, a Deo conditus est.” sed quoniam ipsa organa et genitalium fabrica, et nostra feminarumque discretio, et receptacula vulvae ad suscipiendos et coalendos fetus condita, sexus differentiam praedicant, hoc breviter respondebo: numquam ergo cessemus a libidine, ne frustra huiuscemodi membra portemus. cur enim maritus se abstineat ab uxore? cur casta vidua perseveret, si ad hoc tantum nati sumus, ut pecudum more vivamus? aut quid mihi nocebit, si cum uxore mea alius concubuerit? quomodo enim dentium officium est mandere, et in alvum ea quae sunt mansa transmittere, et non habet crimen qui coniugi meae panem dederit: ita si genitalium hoc est officium, ut semper fruantur natura sua, meam lassitudinem alterius vires superent: et uxoris, ut ita dixerim, ardentissimam gulam fortuita libido restinguat.
(Jerome, Adversus Justinianum 1.36)

Why then, you will say, were the organs of generation created, and why were we so fashioned by the all-wise creator, that we burn for one another, and long for natural intercourse? To reply is to endanger our modesty: we are, as it were, between two rocks, the Symplegades of necessity and virtue, on either side; and must make shipwreck of either our sense of shame, or of the cause we defend: If we reply to your suggestions, shame covers our face. If shame secures silence, in a manner we seem to desert our post, and to leave the ground clear to the raging foe. Yet it is better, as the story goes, to shut our eyes and fight like the blindfold gladiators, than not to repel with the shield of truth the darts aimed at us. I can indeed say: “Our hinder parts which are banished from sight, and the lower portions of the abdomen, which perform the functions of nature, are the Creator’s work.” But inasmuch as the physical conformation of the organs of generation testifies to difference of sex, I shall briefly reply: Are we never then to forego lust, for fear that we may have members of this kind for nothing? Why then should a husband keep himself from his wife? Why should a widow persevere in chastity, if we were only born to live like beasts? Or what harm does it do me if another man lies with my wife? For as the teeth were made for chewing, and the food masticated passes into the stomach, and a man is not blamed for giving my wife bread: similarly if it was intended that the organs of generation should always be performing their office, when my vigour is spent let another take my place, and, if I may so speak, let my wife quench her burning lust where she can. (tr. William Henry Fremantle, George Lewis and/or William Gibson Martley)