Onset of puberty in MX and DZ twins.

A twin study on the significance of genetic factors for the variation in peak height and peak weight velocity, as well as in age at menarche and the development of secondary sex characteristics, is presented. Evidence of a rather strong genetic regulation of the occurrence of puberty was obtained in the analysis. The maximal height or weight gain (in cm/year of kg/year) seems to be, at least in girls, less influenced by genetic factors than the age at which it appears.