From an evolutionary standpoint, it makes sense. Women had to bond together and make a home in their cave that they lived in while men went on hunting trips. It is not advantageous for a man to be gay because obviously he will remove himself from the gene pool.
In a matrilocal group (the women stay with the tribe, women's mates move in) having sons be gay can have advantages for the tribe. A heterosexual son, once grown, is going to move out and join another tribe when he finds a mate, while a homosexual son will be more likely to stay with the tribe and promote the survival of his sister's kids.
Feminism may act to increase the "gayness" of society.