There's a widely held assumption that a slight imbalance in male births has its start at the very moment of conception. But researchers say factors later in pregnancy are more likely to explain the phenomenon. CNRI/Science Source hide caption

itoggle caption CNRI/Science Source

Pregnant doctors are less likely than other women to deliver their babies via C-section, recent research suggests. Economists say that may be because the physician patients feel more empowered to question the obstetrician. iStockphoto.com hide caption

itoggle caption iStockphoto.com

Infants used to be born at home to traditional midwives. Mónica Ortiz Uribe hide caption

itoggle caption Mónica Ortiz Uribe