Washington, Apr 8 : Researchers from Tel Aviv University have shown that the war between the sexes may begin in the womb, and that a male twin can compromise the health of his twin sister before she is born.
The study, led by Prof. Brian Reichman, a lecturer in pediatrics at Tel Aviv University's Sackler School of Medicine, is expected to help pediatricians better understand the health risks and outcome of premature babies.
In the study, Prof. Reichman helped analyze the data collected by the Israel Neonatal Network comprising 8,858 very low birth weight infants (1 to 3 pounds) born prematurely at 24 to 34 weeks' gestation.
The study data covered infants born between 1995 and 2003 and included singletons, same-sex and mixed-sex pre-term twins.
They analyzed the incidence of complications, such as respiratory distress syndrome, found in pre-term twins.
Compared to premature twin boys, premature twin girls had a 60 percent advantage, the study found.
The study also found that the premature twin girls tended not to develop respiratory distress syndrome and chronic lung diseases sometimes found in premature infants. This advantage was lost in infant girls with a male twin.
"The male disadvantage, the study suggests, seems to be transferred from the boy to the girl in utero," Reichman said.
"The effects are occurring already in the uterus," he added. The study is published in the journal Pediatrics.