Let us, however, proceed with our scheme.

We were saying that the parents should be in the prime of life?
Very true.
And what is the prime of life?
May it not be defined as a period of about twenty years in a woman's life, and thirty in a man's?
Which years do you mean to include?
A woman, I said, at twenty years of age may begin to bear children to the State, and continue to bear them until forty; a man may begin at five-and-twenty, when he has passed the point at which the pulse of life beats quickest, and continue to beget children until he be fifty-five.
Certainly, he said, both in men and women those years are the prime of physical as well as of intellectual vigour.
Any one above or below the prescribed ages who takes part in the public hymeneals shall be said to have done an unholy and unrighteous thing; the child of which he is the father, if it steals into life, will have been conceived under auspices very unlike the sacrifices and prayers, which at each hymeneal priestesses and priest and the whole city will offer, that the new generation may be better and more useful than their good and useful parents, whereas his child will be the offspring of darkness and strange lust.
Very true, he replied.
And the same law will apply to any one of those within the prescribed age who forms a connection with any woman in the prime of life without the sanction of the rulers; for we shall say that he is raising up a bastard to the State, uncertified and unconsecrated.
Very true, he replied.
This applies, however, only to those who are within the specified age: after that we allow them to range at will, except that a man may not marry his daughter or his daughter's daughter, or his mother or his mother's mother; and women, on the other hand, are prohibited from marrying their sons or fathers, or son's son or father's father, and so on in either direction.

And we grant all this, accompanying the permission with strict orders to prevent any embryo which may come into being from seeing the light; and if any force a way to the birth, the parents must understand that the offspring of such an union cannot be maintained, and arrange accordingly.
That also, he said, is a reasonable proposition.

But how will they know who are fathers and daughters, and so on?
They will never know.

The way will be this:--dating from the day of the hymeneal, the bridegroom who was then married will call all the male children who are born in the seventh and tenth month afterwards his sons, and the female children his daughters, and they will call him father, and he will call their children his grandchildren, and they will call the elder generation grandfathers and grandmothers.