Age at menarche in a selection of countries. Adapted from Parent et al. (2003). Average menarcheal age is younger in France and other Mediterranean countries compared to other countries in western European countries, differences that might involve not only genetic factors, but the effects of geographical location such as altitude, day light hours, humidity, and temperature. Also noticeable is that age at menarche is similar in Asian and Mediterranean countries.   

                                

See Adolescent growth spurt, Estradiol, Gonadotropin releasing hormone (GnHR), Hereditary, Hormones, Progesterone, Puberty, Secondary sexual characteristics