Homosociality
The social bias towards members of one’s own sex can develop early in children. Specifically, studies have found that by the early age of 3 or 4, children prefer members of their own sex to members of the opposite sex (Bussey & Bandura, 1992). That is, young girls favor other females (girls and women) over males (boys and men). The findings are identical for young boys. Also, Carol Martin (1989) found that boys 4.5 years of age expressed significantly more dislike for a girl depicted as a “tomboy” than a boy depicted as a “sissy”; whereas boys 8.5 years of age express more dislike for a boy depicted as a “sissy”. This age difference suggests that children as young as 4 prefer their own sex regardless of gender-incongruent behavior. Around the age of 8 however, boys begin to show males—devaluing feminine behavior. It has also been shown that children ages 10–12 prefer same-sex socializing. That is, girls favored girls who socialized with other girls and boys liked boys who socialized with other boys.