It's not just child-care, it's husband-care
Echidne is doing a wonderful job refuting the argument that women aren't in the hard sciences 'cause we're dumb and wuv the babies too much to get into math. Anyway, she discusses how time issues are an impediment to women joining the ranks, as they are for men.
Second, why would women react differently to a long workweek than men? This is the hidden agenda in this suggestion: it has to do with who is going to take care of the children. So it's very simple, really: according to this hypothesis, women are not in the hard sciences because they need to have more time for family life. Men appear not to want to have a family life to the same extent. Why would this be the case? Here, once again, opinions differ. Some argue that women have a biological imperative to spend more time chauffeuring their children to hockey meets than men do. Others argue that the upbringing we are all subjected to convinces both girls and boys of the necessity for such tasks to belong to women. Or perhaps both of these reasons apply at the same time....
Talking about the "eighty-hour week" is a shorthand way of pointing out that so many things in the academia assume that the scholars have a well-equipped home base to which they return only to sleep. The scholars are certainly not expected to give birth to children, for example, though change in this has taken place in the last few decades. But hard sciences may not look like very hospitable places to a lot of women for reasons of this sort.
I think it's true that women have less time than men, as a general rule. But it's not just because women take on the lion's share of child-rearing. Lots of women who are always really pinched for time don't have small children to raise, so they should have as much free time as men. But, speaking anecdotally of course, it seems to me that this just isn't the case. A good number of childless women and women whose children are grown that I know are still run ragged. And for the reason that Echidne touches on in the 2nd paragraph I quote from her. That would be the well-equipped home base for the working man.
Caring for the working man is still the job of women. Housework, shopping, laundry, and dinner still fall primarily for women to do. After all, a working man should have a nice home to come home to relax to. And he should, he really should. But unfortunately, the women who do so much of this work usually hold down full-time jobs themselves.
It's my personal theory that many women still do the "second shift" mostly by themselves in large part due to the wage gap. I know that I have many guilt pangs about the fact that my boyfriend pays more into the bills than I do because he makes more than I do. Practically speaking, it's the best way for us to do things. Emotionally speaking, it makes it really hard for me to ask him to do the shopping once in awhile. I feel like I can compensate for what I don't make at work by working extra hours at home. Luckily, he doesn't take advantage of this muddle of feelings, so I do manage to squeeze in plenty of free time. But I'm guessing that lots of people, especially those who are raised believing in "women's work" and "men's work" are perfectly fine having women compensate for making 25% less by working 40% harder.
Whether people think it through that hard or not, I know lots and lots of couples who live with the notion that a woman should take care of her man's needs, and if that means she has no downtime because she has a fulltime job herself, well that's too bad. And of course, if challenged, the genetic, traditional and/or Biblical arguments will come out. Women's work and men's work and all that. If women's work is harder, then that's too bad. Take it up with god and/or nature.
I have no trouble believing that some women are simply worn out by life and can't get ahead because of it. For lots of women I know, their only options to lighten their load are to ask their husbands to take on more housework or just cut back on the amount of housework that is done. And neither seems like a real option, since to take #1 is to be a nag and to take #2 is to be a slob. Very unfeminine. God knows I watched my mother struggle with this conundrum my entire childhood.