SAN DIEGO -- There was this perceptive episode of the ``George Lopez" show where George and his wife Angie are squabbling over who contributes more to the household. They create a point system to keep track of who does what. Before long, George is demanding points for taking out trash or helping his children with their homework.

I get the joke.

This is an ongoing argument in our house, and, from what I gather, many households across the country. You're especially likely to hear rumblings of it in homes with small children and too little time and parents who are fiercely protective of the moments they have to themselves. At the core of this squabble is a simple question with no simple answer: Who does more -- Mommy or Daddy?

Take my advice. Don't go there. In many two-parent families, each parent makes valuable contributions to the family and household, even if we're better at keeping track of what we do than noticing what our spouse does. So it's just as well that a new study has come along saying we should declare this contest a tie.

Conducted by a team of researchers lead by Suzanne M. Bianchi, chairwoman of the sociology department at the University of Maryland, the study analyzed thousands of personal ``time diaries'' where people recorded how they spent their days. The findings were then compared to what we know about how men and women spent their time in 1965.

All this was included in an important new book, ``Changing Rhythms of American Family Life," written by Bianchi and co-authors John P. Robinson and Melissa A. Milkie, also sociologists at the University of Maryland.

Bianchi and Co. gave us a lot to chew on here, and some of it turns on its head the conventional thinking about the division of labor and gender roles. While many women work outside the home, they still devote, on average, twice as much time to housework and child care as men do, the study found. Men spend more time at work than their fathers did a generation ago and yet -- when they get home -- they still find time to help take care of the kids.

I didn't need a study to tell me that. When I get off work, my wife -- who has been home all day with our 2-year-old daughter -- naturally expects some relief. And that's what I provide.

Bianchi insists that, as young dads go, I'm not alone -- despite popular myths to the contrary.

``In the literature, there has been an overemphasis on what men aren't doing,'' she told me, ``and maybe a failure to pay attention to what they increasingly are doing.''

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.