[Relation of age at menarche and fertility period to body composition as related to surface area. A hypothesis].

From the potassium-40 values, the body weight, and the height of 4112 girls and women aged 8 to 65 years, we derive an association between menstruation and body cell mass/surface area quotient. In girls reaching a body weight of 47.8 kg, i.e. the body weight during the menarche according to Frisch and Revelle, the body cell mass/surface area quotient is 16.8 kg/m2 and remains such during the time of regular menstruations.