• puberty
• girl

There has been great recent media interest internationally in claims that puberty is occurring at younger ages, particularly in girls. Pundits extrapolate the plunging graphs of the secular trend in menarche downwards into infancy, postulate epidemics of child sexual experimentation, and bewail the loss of innocence of childhood.

Until recently, most of this debate centred on evidence from the United States, particularly the conclusions of a large national study of puberty in girls published in 1997 by Herman-Giddens and colleagues.¹ The evidence was sufficient for the US Lawson Wilkins Pediatric Endocrine Society to recently revise downwards its suggested age for investigation of precocious puberty in girls,² although this has been contentious.³ Suggestions that puberty was occurring earlier received strong support from lay opinion in the UK, particularly from parents and teachers.⁴ Further energy was given to the debate by the release of unpublished observations from the Avon Longitudinal Study of Parents and Children (ALSPAC, also known as Children of the Nineties) that approximately one in six 8 year old girls had either breast buds or some pubic hair (personal communication, Jean Golding; http://www.ich.bris.ac.uk/alspacext/Default.html).

However, such claims have been met with some scepticism within the field of paediatric endocrinology.³ Although some clinicians report seeing more cases of precocious puberty than a generation ago, single observer longitudinal studies of puberty show there has been little if any change since Tanner and Marshall's original work over 30 years ago.^5,6 The well known graphs of the secular trend in age of menarche from the late nineteenth century seem to invite projections of an ever earlier age of puberty. But it is clear that in developed countries the secular trend has leveled off in the past 40 years. Indeed, there is …