Augustine on Allegory

Augustine's assertion that "men of old" (66) had several wives solely for continuance of their race is impractical. Thinking in a purely biological sense, Augustine's reasoning that these men "looked only to the procreation of children in the sexual act" (61) in ancient times would be reasonable if they had no sex drive. This would mean castration or removal of the pituitary gland, both impractical in old times. (I'm guessing that old times refers to the middle ages). Secondly, the infant mortality rate was much higher and life expectancy much lower than today or even in Augustine's time. Therefore the value placed on a person's life was very low, allowing for less inhibition. But the idea that men of old would "immediately have castrated themselves for the sake of the kingdom of heaven" (62) in present times is absurd. This is purely wishful thinking on Augustine's part. A sort of selfish gene keeps people from doing this to their bodies. In the perfect world, everyone would be moral and just according to the golden rule. But this world is far from perfect, and the idea that everyone is chaste who follows scriptures in the right way according to love in Augustine's rationale does not happen in practice.