Goldstein, Joshua R.; A Secular Trend toward Earlier Male Sexual Maturity
Evidence from Shifting Ages of Male Young Adult Mortality

Improved nutrition and disease environments have generated substantial increases in human body size over recent centuries. A decline in the age of menarche, the measuring point for the onset of female sexual maturity, has also been well documented.
A similar shift to earlier ages of sexual maturity for males has been hypothesized, but evidence of a long-term trend has been elusive. The secular trend toward younger menarche can be documented because individual health records recording first menstruation can be compared over time.
For males, however, no such comparable medical evidence exists.
The research reported here takes an indirect approach to measuring males' age of sexual maturity.