When both parents are employed, mothers still take on significantly more child-care duties than fathers do, according to a new study out of Ohio State University. The study was based on time diaries of 182 middle-class couples in which both parents worked. When the children were 9 months old, on an average work day, the mothers spent 70 percent of their time outside of work performing some sort of child-care task, versus less than 50 percent of time for the dads. The results showed that moms spent more time even after excluding breast-feeding and pumping from the time tally.