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.
Where did the story come from?
Dr Marco Procopio of the University of Sussex, Brighton and Paul Marriott of the University of Waterloo, Ontario, Canada carried out this research. No sources of funding were reported by the study. The study was published in the (peer-reviewed) medical journal: Archives of General Psychiatry.
What kind of scientific study was this?
In this cohort study of more than 12,000 pairs of Swedish twins, the researchers examined the rates of anorexia in same-sex and opposite-sex twins to investigate whether exposure to sex hormones in the womb affects brain development and causes a predisposition to anorexia nervosa in later life. The researchers suggested that when a male and female share the womb, the mix of hormones during development means that there is feminisation of the male and masculinisation of the female, and that the presence of a male in the uterus may be expected to protect against anorexia for the female or increase the risk in the male.
