Ward Cleaver has been replaced by a stock character known in the trade as Doofus Dad. Explaining this change isn't easy, but if Ward were still around, he could puff his pipe and offer several theories.

The most obvious is that the television audience has splintered along gender lines, and sitcoms are now a female domain. Four out of five viewers of network sitcoms are women, and they apparently like to see Mom smarter than Dad.

Another explanation is the rising number of mothers with paying jobs. Now that they have their own paychecks, the old bread-earning patriarch is less essential and therefore more mockable. And TV writers no longer have an easy stereotype of Mom to work with. Jokes about daffy middle-class housewives like Lucy Ricardo and Edith Bunker seem dated now that so many women work outside the home.

Fathers are still the same old targets, and they're even more tempting now that they've gotten a new image as shirkers thanks to widely reported findings about who does what at home. Even though more mothers have outside jobs, women still do about four more hours of child care and four more hours of housework per week, according to studies by the social scientists John Robinson and Geoffrey Godbey.

But it's not as if these women's husbands are out every night drinking at Moe's. The same studies show that men have increased their share of the child care and housework while still working 14 hours longer outside the home than mothers do each week. Overall, the men still have a little more free time -- about a half-hour per day -- but that gap has been shrinking, not growing, in recent decades.