Are sons bad for your health? A Finnish study finds that women who had several don't live as long after the last birth as do women who have daughters. The research, however, may be a bit dated: Researchers reviewed 300 years of parish data, and most of the women involved were born before 1960, LiveScience reports. In the records of 11,000 women, authors found that more sons were tied to shorter life spans after the final birth.
"Girls in many traditional societies are, as we know, much more helpful to mothers than boys," says an expert who didn't work on the study. "They may help with child care; they may help with many tasks." Also, boys' tendency to be heavier babies could mean they require more nutrients from their mothers during pregnancy and breast-feeding. On the other hand, in societies like China, sons appear to be linked to longer maternal lives. Either way, in a post-industrial society with birth control and more food availability, things may be different today, an author says.