Changing times: the evolution of puberty.

An evolutionary and life history perspective is used to consider the evolution of puberty. The age of menarche would have evolved by the Neolithic to be matched to social maturity. It is suggested that in developed countries menarche is now returning to a similar age as in the Neolithic as infection and undernutrition, features of post-Neolithic society, have reduced impact. But recently the psychosocial expectations on adolescents in western societies have changed and social maturity now significantly follows menarche. The implications of the developing mismatch between the ages of biological puberty and social maturation are discussed. Evolutionary arguments are presented to explain the unique pubertal growth spurt of humans. Moreover, a life history perspective can reconcile the apparently conflicting observations that both poor fetal growth and better childhood nutrition are associated with earlier menarche.