OK, if traditional views say women are supposed to do the cooking, why are most chefs in restaurants men?
Cooking all day is strenuous. There are plenty of women who cook a lot, but they are all stong armed.
They’re also bosses of crews that tend to have a large proportion of rowdies and misfits, so the general prejudice against women in positions of authority plays a role.
If the woman is at a RESTAURANT cooking, it means that she’s NOT HOME cooking for her FAMILY! 
<runs for cover>
In all seriousness, I’d bet that it was something like this when it started, and has just been “tradition.” It seems as though we are getting more women chefs as time goes on, and women begin to break into the higher ends of the professional kitchen.
While we’re waiting for one of the Doper chefs to arrive, I’ll just say that there’s a great deal more to being a top chef than cooking: you’re organising all the other staff, for instance.
This isn’t exclusive to cooking. Women cook, men are chefs. Women teach, men are highly respected professors. Women sew, men are tailors and fashion designers. Women garden, men farm, even.
Why? Oh, I’m sure we could come up with some feminist philosophy about the patriarchal attitudes of our society automatically elevating professions once men do them, with higher pay and social standing as some of the perks. We could point out that women are, more of the time, restricted in their vocational advancement because of the duties of family care. Taking time off to have babies and sick days to take your kid to the doctor are not ways to get ahead in the cutthroat restaurant industry (and, even in dual income families, these things are more often done by mom). Or it could be the other way ‘round - men don’t get into fields until the pay and social perks are worth it - I’m seeing this happen right now in nursing. With the nursing shortage, pay scales are increasing, and more men are choosing nursing as a career than before. We’re even getting rid of the dreadful “male nurse” label. We could hypothesize that once a few men get into a field, they’re more likely than not to drive women out of that field, through hiring other men through a "good ol’ boys" network or simply acting like testosterone crazed chimps (again, I’m specifically thinking of high end, high stress kitchens here.)
In reality, it’s probably all of these and even more. Complex issues like this rarely have only one “right” answer.
WhyNot is moving in the right direction, but focuses too much on today. The roots of this lie in history and the perceptions of women as creatures of the home and men as professionals who are allowed to do business with other men.
There are no traditionally female professions, unless you count prostitution. Professionals were creations of the upper class, those who had the money to buy experts to work for them. The upper class were as ridden with sex-laden preconceptions and prejudices as anyone, most of them devolving from the absolute power of the king. (There were a few queens in history, but they are rare and in some hierarchies forbidden.) Men controlled the household and the checkbook. They would not deal with a woman professional, even if by some bizarre chance a woman could gain the skills to become a professional.
After the industrial revolution, wealth moved from the upper class to a new nouveau riche class, and the number of professions and professionals boomed. The attitudes stayed the same, however. Chefs ran restaurants and were men. Tailors ran establishments and were men. Men were teachers and professors, doctors and lawyers. Men ran financial institutions, commercial establishments, and industrial applications. There was no place for more than a very few exceptional women to fit in anywhere. Public teaching held that women were intellectually inferior, so you wouldn’t want a woman in any of these positions. When an obviously intellectually equal woman appeared, she would be derided as a freak.
The change came only in the 20th century. World War I was the first total war, the first war that drained off such a high percentage of the young men in the majority of countries that women were needed to take their places to keep the country and the war effort running. This helped women’s suffrage in the U.S., for example. There had been a few examples of this earlier, when teaching and nursing started becoming women’s professions because of the shortage of men to fill these jobs, but that was actually counterproductive, because it lowered the status of those professions and raised the status of the inviolate professions of doctor and professor. After WWI, attitudes quickly reversed and women were pushed out of the workforce.
The same pattern emerged even more strongly during and after WWII, but the backlash to that was so strong that this time women regained their foothold in the male world.
And yet… Women are increasingly the majority in many professional schools, although it will take a generation for this to work its way through the tops of the fields. But most chefs still are men, mostly because cooking has been dominated by men and is one of the last holdouts of the older attitudes. Eventually this will also change. It’s just taking longer.
All of these statements are true, though I think the latter is no implicit strike against women. Anyone who has seen the secretary/executive assistant of a corporate exec at work will realize that women as a general category are no less capable of this than men.
The answer to this is that being a cook, and especially an executive chef, is a very demanding and time consuming job that has only a modest amount to do with actually cooking (at least, compared to what Mom does in the kitchen), and is comperable in effort to any high pressure professional career, sans the mid-six figure paycheck and golden parachute; we’re talking 12+ hour days, 6 days a week, leaving little time for, say, raising a family. People who are cooks do it because they love the type of work and (typically) don’t want or can’t cope with a normal-type life. It’s also a career with a lot of machismo, frat house pranksterism, locker room humor, and a high burnout/substance abuse rate. All of this, combined with the fact that it’s not a traditional career for women, means that men are more heavily represented. Also, many line cooks are immigrants from countries where men traditionally hold all jobs, so there’s a cultural tendency there for the men to work, even if women do all of the cooking at home.
In the few kitchens in which I’ve worked it would take a very “butch” woman to hold her own in that environment. (I don’t mean gay, but able to take and receive insults and affronts without screaming “Sexual harassment!” every ten minutes; basically, a chick who can really be “one of the guys”.) This may not be true of all commercial kitchens, but it’s the culture in enough of them to make it a difficult situation for a women who wasn’t brought up to be assertive.
However, the number of graduates from culinary schools is basically at gender parity these days, and there are plenty of women cooks, bakers, and chefs who have made big names for themselves, so it’s hardly unheard of, either. The representation of women among the ranks of executive chefs is probably lower than the general population of professionals owing to the relative conservatism of high end restauranteering, but it has grown significantly in the last couple of decades.
Stranger
Or it could be that we’re better at everything. 
I’m sure that’s it.
I’d have to disagree with the ‘women in the kitchen’ statement. Most of the men I know (including myself) enjoy cooking more than our female partners. Quite a few even prefer to shop for the food, so making sure the best quality is hunted out.
BTW we prefer Japanese knives to pink aprons as accessories.
This is an obsolete question. The first part assumes the long-ago time when men worked and their wives stayed home doing “women’s work.” In those days, most men didn’t cook at home, and they didn’t want to. The second part ignores all the female chefs we have today.
Forget Ward and June Cleaver. Even back then, they were fiction.