Yes, childbirth and raising is a very good point. But that shouldn’t lower the averages because working mom’s can easily go back into the workforce and kick ass and get paid the same or more than a man. Nor should it affect the score of averages. More men are becoming stay at home dads and single dads work. While this does mean that women are often not in the workforce very long, it does not mean that those who are in the workforce are being denied equal pay.
It’s very very very tricky.