Explainer: why do women go through menopause?
Menstruation is a reproductive quirk that humans share with only a few other mammals. But even stranger is the fact that women stop menstruating when they have a whole third of their lives left to live. All animals have a finite reproductive life. But more often than not, their reproductive system winds down at roughly the same time as every other system in the body – the menopausal killer whale is a notable exception. The ability to bear children gradually declines throughout a woman's reproductive life. The average age at which a woman's ability to natural conceive ceases is 38. But when the fertility free-fall of menopause kicks in between the ages of 45 and 55, complete sterility is the inevitable result. No more ovulation, no more menstruation, and no more opportunities to procreate. In contrast, males experience only a slight decrease in fertility in their senior years. Giving kids a head start Evolutionary theory predicts that life span and reproductive span should synch...