We know that the Spartan community was nearly 100% homosexual. Heterosexual sex was performed on the wives to breed additional soldiers but once they impregnated the women, they returned to the ranks. Homosexuality was believed to create greater cohesion among the troops.
Male children were taught at an early age that this was what would be expected of them as they matured. In other words, it was cultural. It was nurture - not nature. And history is replete with examples.
then I stand corrected.