Scientists claim the age of a girl’s mother – not her diet – has the biggest influence on when she starts her first period

A study shows that genetics explains more than half of the variation between women’s ages when menstruation began. Scientists at the Institute of Cancer Research, a college of the University of London, found that a woman’s age of menarche - when periods begin - was significantly linked with that of her relatives, including her mother, older sister, grandmother or aunts. They used mathematical modelling to find that genetic factors accounted for around 57% of the variation in the age of menarche of women. The age at which menstruation begins is important because it has been linked to a risk of number of chronic diseases including breast cancer. Risk of breast cancer gradually increases with a progressively younger age at first period, and older age at menopause, possibly because women are exposed to female sex hormones for a longer period of time.