The Secular Trend in Puberty: Has Stability Been Achieved?

S ummary . An investigation is described in which data concerning the age of menarche were obtained from a sample of girls in three West Riding schools. Every care was taken to ensure the accurate reporting of this event. When the figures were compared with those obtained earlier from a closely similar group, a discrepancy of six months in the median age was noted. This is explained in terms of an artifact resulting from the method of reporting the event. When the more recent figures were compared with data obtained from other surveys conducted in the last sixteen years, no consistent secular trend was revealed.