characteristics that determine gender

Gender is determined by sex chromosomes, by internal and external genitals, by sex hormones, and by psychological factors. Pseudohermaphrodites are XY with male internal genitals, but are deficient in one of the male hormones that trigger formation of external genitals. Thus they are born looking like girls. At puberty, however, more male characteristics begin to develop. Testicular-feminized males lack androgen receptors so their testes fail to descend and
their brains are not masculinized, and their outward appearance is female, though they are sterile. Adrenal tumors can secrete hormones that masculinize or feminize the opposite genetic sex. Sometimes psychological gender identity fails to match genetic sex, for unknown reasons.