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
Male reproductive system male reproductive system is the process whereby the reproductive organs grow, mature and are established. It begins with a single fertilized egg and culminates 38 weeks later with birth of a male child. It is a part of the stages of sexual differentiation. The development of the male reproductive system coincides with the urinary system. The development of them can also be described together as the development of the urinary and reproductive organs. Sexual identity is determined at fertilization when the genetic sex of the zygote has been initialized by a sperm cell containing either an X or Y chromosome.