Data are presented on age at menarche and adult stature in 905 women from the islands of Lewis and Harris, born between 1920 and 1949. Menarcheal age showed no tendency to fall in women born between 1920 and 1935, but thereafter successive year-of-birth groups showed an almost continous decline. There were no significant changes in stature in successive groups.
The changes have been correlated with trenda in affluence, as indicated by unemployment levels. In women born between 1932 and 1941 there was good agreement between average unemployment during various periods of childhood and menarcheal age, but among later-born individuals the relationship broke down. It is suggested that during the earlier period unemployment was associated with some degree of biological deprivation, but that during the later period the introduction of rationing and later, of the Welfare State, buffered the growing child against economic hardship.
Mean household size (used as an estimate of mean sibship size) fell over the period of study, but its pattern of change was different from that of menarcheal age. It is suggested that this factor played at most aminor role in fluencing the results of the investigation.