Over the past 150 years, the age of puberty onset has fallen substantially across many developed countries. Although trends are apparent in both sexes,¹ the evidence in females (where biological markers are clearer) suggests that, for instance, in northern Europe the age at menarche (first menstruation) fell during the 1800s, then further reduced by up to 3 years over the last century (fig 1). Factors contributing to this fall include a combination of public health successes and changes in social structures. Thus, successes such as improved childhood nutrition and health status through reduction in childhood infections have been major factors accelerating the onset of puberty.⁷

Socially, however, stress is also a puberty accelerator, with familial disruption, including father absenteeism, being one of the most effective stressors, and levels of divorce as well as single-parent families have rapidly escalated in many countries (eg, England, 2005).^8,9 The sum effect of these changes has been relatively recent reductions in the age of puberty onset.⁷ However, these have not been matched by efforts to …