Pubertal development in black and white Johannesburg girls.

A study of the sexual maturation of 362 black and 355 white girls was conducted in Johannesburg in 1976 and 1977. It was found that the first sign of breast development occurs at the same mean age of 11.5 years for both groups, but that white girls develop pubic hair and experience menarche some 9 months earlier than black girls. The menarche in black girls occurs at a younger age than that recorded in the 1960s. The average black girl reaches full maturity later and has a longer maturational period than her white contemporary. In addition the time-span between maturational events in black girls differs from that in white girls.