Causes of transsexuality Docter and others, but opposed by Charles Allen Moser, Larry Nuttbrock, Julia Serano, and the World Professional Association for Transgender Health.<section end="factors" /> A 2008 study compared 112 male-to-female transsexuals (both androphilic and gynephilic), mostly already undergoing hormone treatment, with 258 cisgender male controls. Male-to-female transsexuals were more likely than cisgender males to have a longer version of a receptor gene (longer repetitions of the gene) for the sex hormone androgen or testosterone, which reduced its effectiveness at binding testosterone. The androgen receptor (NR3C4) is activated by the binding of testosterone or dihydrotestosterone, where it plays a critical role in
Human male sexuality with a male, and decrease the chance that the female will mate with another male. There are several strategies by which sexual coercion can be achieved. These are harassment, intimidation, and forced copulation (rape). Thornhill and Palmer's "A Natural History of Rape" investigates the evolutionary causes of sexual coercion, particularly of rape, and suggest that such behaviour is a result of sexual selection, rather than Darwinian natural selection. Of ten listed hypotheses, they accepted two reasonable hypotheses: Thornhill and Palmer argue that these two theories are the strongest of the ten for several reasons. For example, both hypothesis argue rape