I agree, Trainspotting. A lot of people still feel that it's somehow unnatural for mothers to want to work outside the home. It's socially acceptable however, if they need the money.
Someone made a comment above about biological differences meaning that women are more likely to want to stay at home with their children. Someone else used the phrase "maternal instinct". All of these ideas play into the idea that it's right and proper for women to stay at home and somewhat unnatural for them to want to work if they don't have to.
I've no doubt that many women do want to stay at home with their kids and that's fine, but I'm less than convinced that this is biological in origin.
Yes, most women have an instinct to nurture their kids, and I was no exception to that. It's why I breastfed dd for nearly three years and co-slept with her among other things. That didn't mean that I was willing to give up all that I had worked for, or that I felt I was the only person who could care for her effectively.
Similarly, DH had a strong instinct to nurture and care for our dd as well. Yes, it was probably easier for me to bond with her initially, not least because I was feeding her myself. However, by being as involved and hands-on as he was from the outset, I think dh soon developed a really strong bond too.