Anorexia could be determined by exposure to sex hormones in the womb, reported The Times on New Year’s Eve. The female sex hormone oestrogen “may be overproduced by some mothers, affecting the baby’s brain and making it susceptible to the eating disorder”, the newspaper said.
The newspaper reports are based on research into twins that has found that, although anorexia occurs more often in females than males, when they looked at twin pairs of different sexes, males who had shared the womb with a female were ten times more likely to develop anorexia in later life than if they had been in the womb with another male. However, anorexia is a complex psychological condition, and this research cannot prove that the higher rate of anorexia amongst girls, and boys of mixed twin pregnancies, is caused by higher exposure to sex hormones in the womb, and not by a number of other genetic, environmental or social factors.