There are so many people online saying "there is no pay gap", or "there is a pay gap". Often it's really hard to get clarity on an apples-to-apples comparison showing data that demonstrates the pay gap.
Here's a link to a study showing a pay gap in the first year after college. This ignores the problem of lost wages because of maternity leave, and also differences in negotiation (which is debatable - apparently some studies have shown that women who negotiate salary are penalized). If there's good research on that, send me a message!