Anorexia in twins

A new study of nearly 4,500 twins has found that men who have a twin sister are more likely to develop anorexia than other men, including those who have a twin brother. The study of Swedish twins born between 1935 and 1958 found that female twins were more likely than male twins to develop anorexia but where one twin was male and the other female the man's risk was as great as the woman's. The authors suggested that "a plausible explanation for this phenomenon is that in pregnancies bearing a female foetus a substance is produced, probably hormonal, that increases the risk of having anorexia nervosa in adulthood".

You can find out more about this research at

http://psychcentral.com/news/2007/12/05/males-with-female-twin-risk-anorexia/1616.html