Answer:
This debate is widely known and assumes a pathriarchy structure. Men understands that, since women can have babies, it is ok to pay less since at somepoint she will have kids and work less. First: not all women want to have kids. Some women just want to keep working. Second: Women need men to have kids. Kids are everyone's business, not only women, so you lower women's pay and do not allow for men to have days off, you assume that only women have responsability over the child, what is not true. Everyone can have kids, at some point, so the wage should be equal for everyone, just as the days off to take care of a newborn and for children's sick days, for example. The fact that less women have majors in college is due the fact that women started being able to go to college not long ago, and they still have more problems maintaning themselfs in college for multiple reasons.