Battle of sexes begins before birth

LONDON: The battle of the sexes begins even before birth, in the womb, spelling adverse consequences for babies later.

A new study analysed the incidence of complications like respiratory distress syndrome found in pre-term twins. Premature twin girls were better off than their male counterparts by 60 per cent and less likely to develop respiratory distress syndrome or chronic lung diseases sometimes found in premature births. Conversely, a male twin can compromise the health of his twin sister before birth. The disadvantage seems to be transferred from the boy to the girl in the womb.

Brian Reichman of Tel Aviv University  helped analyse the data collected by the Israel Neonatal Network, comprising 8,858 very low birth weight infants (one to three pounds) born prematurely between 24 and 34 weeks’ gestation. 

The study data covered infants born between 1995 and 2003 and included singletons, same-sex and mixed-sex pre-term twins. “The effects are occurring already in the uterus,” said Reichman, citing studies showing that females with male twins may be more masculinised later in life.

A paediatrics commentary on the research said: “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,” co-authors David K. Stevenson and Jon E. Tyson write. The findings were published in Paediatrics.