"I read The Symposium"
by cm

Public DomainAristophanes
The Symposium by Plato includes the speech by Aristophanes on the origin of homosexuality:

Men who are a section of that double nature which was once called androgynous are lovers of women; adulterers are generally of this breed, and also adulterous women who lust after men. The women who are a section of the woman do not care for men, but have female attachments; the female companions are of this sort. But they who are a section of the male follow the male, and while they are young, being slices of the original man, they have affection for men and embrace them, and these are the best of boys and youths, because they have the most manly nature.  The Full Speech

The Symposium by Plato