Girl Fetuses Are More Likely to Be Infected

Girl fetuses are twice as likely to be infected with HIV while in the wombs of their HIV-positive mothers than boy fetuses, European researchers report in the January 23 edition of the journal AIDS. The researchers found that of all infants in the European Collaborative study that were born to HIV-positive mothers through caesarian section, which eliminates the possibility of infection during labor and birth, 6.23% of the girls and 2.8% of the boys were born HIV-positive. 'On the crude assumption that infections among infants delivered by [caesarian section] without labor and before membrane rupture are a proxy for intrauterine transmission, our findings suggest that transmission before 36'38 weeks may be more common in girls than boys,' the researchers concluded. They theorize that the transmission risk difference could 'reflect underlying genetic or immunological differences between the sexes' and could indicate that female and male fetuses become infected with HIV at different times while in the womb.