My wife took time off from work to be at home with our four kids and as they've gotten older, she's starting to get back into the labor force. She is a math teacher and geometry and algebra haven't changed much in the last eight to ten years. Although there are fads in how they're taught, I have to say, which she's going to have to reacquaint herself with. But presumably, women who choose fields that are more dynamic, such as medicine or the technological fields you mentioned, presumably they choose to spend less time out of the labor force when they do have children or they choose not to have children.