“Differentiation of human sexual orientation, particularly bisexuality, has been little studied. Most studies have lumped bisexuals with homosexuals. Some authors have overgeneralized the results of animal studies as applying to humans. While animal models can provide useful hypotheses, human sexual orientation is unique. Therefore, conclusions about human sexuality based on animal research are suspect. Human sexual orientation is influenced by biological, cognitive, cultural and subcultural variables in interaction, leading to multiple types of heterosexuals, bisexuals, and homosexuals. Understanding of human sexual orientation will improve only if these factors are accounted for in research and theory.”