What is so magical about the age at onset of puberty in humans — currently set at approximately 11 years of age?¹ Why not 6 or 16? Indeed, addressing this question from the perspective of evolutionary biology² suggests that puberty, as defined by age at menarche in girls, was earlier in Neolithic times and became delayed during the Industrial Revolution before reverting over the past two centuries to the present set point.³ The shortened life span and the need to reach reproductive capacity would seem to have been predominant influences on the age of menarche thousands of years ago, whereas .�.�.