A study of the biological importance of grandmothers may explain the biological puzzle of menopause as well as one remaining gender inequity in China.

Two studies in the February 7 issue of the journal Current Biology are being lauded for confirming a theory about the value of young grandmothers. Nearly all animals reproduce until they die because natural selection would seem to favor having as many young as possible. So why would humans be an exception, with the female shutting off reproduction (menopause) by age 45-50? The “grandmother hypothesis” suggested that they may shift to caring for grandchildren and thereby increase the chances that the grandmother’s genes will survive.