Boys with twin sisters appear to be more at risk for developing anorexia nervosa than other males, including those with twin brothers. That's according to researchers.
Researchers from England and Canada analyzed data on twins born between 1935 and 1958. They say exposure to female hormones in the womb may explain the increased risk.
Anorexia is about 10 times more common in women than men.
Researchers say the risk among males with a twin sister was not statistically different from that of females with a fraternal twin sister.