November 5, 2009 --Twins may fare better if they share the womb with a sister rather than a brother. Researchers in Israel studied more than 2,700 twin pregnancies. They found that risk of premature delivery was highest when both twins were male and lowest when both were female.
The risks of some complications, including lower birth weight and newborn breathing problems, were higher among babies who had a male twin rather than a female.
The study is in the journal Obstetrics and Gynecology.