Age at Menarche

CLINICIANS are often asked by concerned parents whether their daughter's age at menarche is abnormally late — or abnormally early. In answer, it may be said that what is normal for a particular girl depends upon her genes and life history as well as the common characteristic of human females to start to menstruate at sometime during the second decade of life.For each species of mammal, a characteristic period elapses between birth and the development of full sexual function. In normal girls evidence of sexual maturation characteristically appears not at four or 40, but at eight or 10 or . . .