Both homosexuality and heterosexuality are necessary for the development of the human species and advancement of our society. We were not all born to simply breed and die.

There is a distinct evolutionary advantage to have a segment of your population unencumbered by children. Individuals without children tend to take higher risks and can devote more time to "hunting and gathering" thus strengthening the "tribal unit" by providing resources without the associated mouths to feed. Genetically speaking this gives a distinct advantage to one gene pool over another.