So in the grand experiment of human nature. Heterosexuality and parental desire is required for long run calculations.
The random factors of biology, demonstrate a 3 gland system. You be more easily latched to a time. By a drug that drives love and numbs pain. Less than 15% meet the biological definition of not being long run calculators. So in a room of 20; 3 don't reproduce.
Boy latched onto a girl is still chemically driven heterosexuality. How the girl utilizes the boys release of opiates is, assumed mutual. Even if later mutually stupid.
I think currently we speak to much about sex and not about what happens when father's and mothers leave impressions on their children and their goals for their children.