The battle of the sexes begins in the womb, say researchers from Tel Aviv University. In a new study published in Pediatrics, Prof. Brian Reichman analyzed the incidence of complications, such as respiratory distress syndrome, found in pre-term twins. When born premature, girls who share the womb with a boy twin lost the respiratory health advantage normally seen in premature female infants. "The male disadvantage, the study suggests, seems to be transferred from the boy to the girl in utero," said Reichman.
Compared to premature twin boys, premature twin girls usually had a 60 percent advantage in avoiding respiratory complications. The premature twin girls tended not to develop respiratory distress syndrome and the chronic lung diseases sometimes found in premature infants. This advantage was lost in infant girls with a male twin.
Usually, twin studies tend to focus on what happens after birth, when complicated environmental and learned behavioral factors come into play. But, says Reichman; "The effects are occurring already in the uterus."
Commenting on the research, Dr. David K. Stevenson, from Stanford University, noted that; "For the time being, there remains some biological truth to the old nursery rhyme that boys are made of snakes, snails and puppy dogs' tails, and girls are made of sugar and spice and everything nice. Perhaps nature knows something we do not."
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Source: Tel Aviv University
