In 2000, dads spent an average of 6.5 hours a week on child care activities. That's up from the 2.6 hours a week that dads devoted to child care in 1965, back in the days when taking care of the kids was often lumped together with other kinds of ``women's work.'' For married mothers, the time spent on child care activities increased to an average of 12.9 hours a week in 2000, from 10.6 hours in 1965.

Add it all up and take into account both paid and unpaid work, the study contends, and the number of hours spent on all work endeavors by mothers and fathers is pretty much equal. The total workload? An average of about 65 hours per week.

The study came with surprises. Despite the fact that women represent a greater percentage of the work force than they did 40 years ago, women spend as much time with their children today as their mothers did in 1965.

And despite what we took from the women's liberation movement about how progressive men could stay home while women went to work to support the family, there is a built-in tendency to return to traditional roles.

``Men retain a pretty strong feeling that it's their responsibility to be the economic provider for this child,'' Bianchi said, ``and that sort of pulls them, if anything, to working a little bit longer than they did before.''

Meanwhile, women also snap back to what's expected of them and what they expect of themselves.

``When women moved into the labor force -- as mothers -- they didn't relinquish this feeling of obligation that they're the caregivers,'' Bianchi said.

So even with all the division of labor, in the end, moms are moms and dads are dads. And, in an ever-changing world where many of our traditions seem open to negotiation, that much is awfully reassuring.