There actually exists evolutionary explanation for homosexuality. Group (family) can actually benefit (genetically) if one member is gay. Let me make an example:
Person A (heterosexual) has three sisters and they are all heterosexual. They will marry and raise one child each. That means that this family, let's call it A will have 4 children totally.
Person B (homosexual male) has three sisters and they are also heterosexual, but what is the difference? Since person B is homosexual and as such can't have his own children, he'll be able to help each of his sisters to raise one child more than sisters in the A family. Since each of B's sisters will have two children each that means that family B will have totally six children despite the fact that person B is homosexual. On the contrary persons B homosexuality is genetically beneficent to family B because they will have more children and more genes transfered into the next generation than the A family. Person B can help his sisters to raise one extra child because he doesn't have his own and as such he can divert his resources and time into raising his siblings.
Homosexuality isn't limited to Homo sapiens species only. There exists a subspecies of chimpanzees in Africa called bonobo, their whole social structure is based on sex. To put it simply they use sex as a way of reducing social tension. When any bonobo individual is annoyed or irritated he can just "hump" on his/her's clan mate and reduce the tension. Gender is irrelevant.
Conclusion: Homosexuality is perfectly natural phenomenon.
One time I was in the coffee bar with a friend and on the couch next to our table one couple practically had sex. Ok they were dressed, but they were cuddling so intensively that we thought that they will engage in sexual intercourse in just a mater of minutes. I'm straight but that was repulsive.
Gay is OK!
