The fact that homosexual behavior exists in nature amoung other species should indicate something but I guess this board member doesn't want to acknowledge that.Homosexuality (in human beings) is typically defined as having a preference for sex with the same sex.
Give me some examples in the animal kingdom where that is the case.
The examples I've seen have been either instances of triggering intercourse behavior by coincidental combinations of conditions that merely get near enough to the natural set of conditions to start the response, like, for instance, a dog humping your leg, or erractic responses to unnatural surroundings, like, for instance, all male herd animals kept in a crowded pen under bright, 24 hour flouresent lighting.
I seem to remember some instances of male birds of some species establishing some kind of life relationship, though details weren't provided.
If someone believes in evolution, the notion of normal homosexuality must be absurd, and if one believes in Intelligent Design that notion must mean the Designer is a nihilist.