Abstract: There are many theoretical models, postulated by evolutionary psychologists, for explaining the evolution mechanism of homosexuality; including heterozygote superiority, fertile females, hypervariability, kin selection, group-selection, alliance formation and parental manipulation. In the present review, these theoretical models were systematically introduced, and comparised with each other. These evolutionary psychological theories were also comparised with that of other schools for revealing a more convincible model. The future research should be focused on the sex differences, the exact location of the gene affecting the sexual orientation, and so on.

Key words: homosexuality, evolutionary psychology, theoretical model, gene