The
link I provided contains data for 60,746 men, and 48,334 women - a pretty nice sample size. The men make an average of $895 per week, while the women make $726, a difference of 18.8%.
Let's play a game where we imagine we have 50,000 each of men and women, and try to find that 18.8%.
If we assume that all of the men work 40 hours per week, we have 104,000,000 hours of labor per year. For your theory - that hours worked accounts for the wage gap - to be true, the 50,000 women would have to log 19,552,000 fewer hours (18.8%) than their male colleagues.
Now, there are approximately
72,000,000 women currently in the US labor force, and we currently welcome something like
4,000,000 babies to the US per year. If we assume that those are all single births (obviously untrue), and that all women who give birth are employed (also obviously untrue) we find that 5.5% of currently-employed women miss work due to childbirth. This comes to 2,750 of our group of 50,000.
If we assume that all of them take the maximum 12 weeks of unpaid maternity leave (untrue) allowed to them by law, and that they would only miss 32.5 hours per week instead of 40 (18.8% fewer), we find 1,072,500 of the 19,522,000 fewer hours we're trying to account for.
So there are 18,449,500 missing hours still to be found - or 390 hours each for our remaining 47,250 women who did not have a child. So those 390 hours are, what, laziness? The average women is lazier than the average man to the tune of almost 10 weeks per year? Give me a break.