Why we need opposites?

Opposites aren't just gender... And gender is defiantly not the most important thing, nor are humans. There's a balance to that keeps everything going... And in order for the balance to be kept an order must be obeyed. where there is shadow there is light, where there is fire there is water, where there is earth there is wind, and where there is death there is life. Balance.

sometimes some males need males, some females need females.....

because reproduction?

Some of us like sameness. : )

genius