Like this matters at all.
As far as less pay for women, it might make sense to wikipedia Simpson's paradox. A lot of confounders at work I'm sure on this. I'm the first to say b*tches get a bum rap, but in the world of GME each PGY gets what they get, I can't believe gender factors in at all for gross salary. Granted, if a female resident is more likely to take unpaid leave or have child-related expenses, that would be a factor in their budget but even I can hardly say that the program should pay a female worker more because she has a certain amount of fixed expense for childcare a male colleague does not. That's what tax credits and other societal support structures that may or may not be in place are there for.
It doesn't matter at all because I hardly think resident pay should be anything but the lowest consideration. What counts more are things like competitiveness of specialty, fellowship considerations, research opportunities, geographics like cost of living in area, safety, commute, plans to buy vs rent in the area, childcare, schooling opportunities for kids, spouse employment opportunities, family distance, call schedule, rotation schedule, what rotations, vacation time/pay, what are terms of healthcare insurance (these can vary greatly residency to residency all else being equal), plans available, monthly premium, adding dependents, prescription drug coverage, copays, deductible, out of pocket maximum
That was a jumble but can be divided into things that will impact quality of life, and factors that affect take home pay (state taxes, employee contribution to medical/dental) and how far take home pay takes you given cost of living in area and where else your money has to go (kids, etc).
Some residencies do not technically provide health insurance, in that the resident has to buy their own through the health exchange and I'm not sure then what the program has to do as an employer towards that, or some frankly don't offer much better than catastrophic or crazy high deductible, residents may be checking off the wrong box because the health benefits are such that they are so bad that it may as well have been none.
I don't know exactly how Obamacare played in to this, I do know that some places health benefits were shockingly bad almost lacking to a point that when I looked at programs (before Obamacare was full force) there were programs I couldn't even consider because of what my out of pocket would have been in comparison to salary.
My program was pretty good in this regard except that premiums, deductible, copays, prescription drug coverage, up to out of pocket maximum meant a guaranteed 6K right off my salary.
But that was better than places where coverage for my meds would have left me paying $1500 a month out of pocket.
If you have any chronic conditions or your family does, you definitely need to read the fine print on the programs health benefits, etc, that will make more of a financial difference that you'll feel than the gross salary differences program to program.
In fact, most of the time the little contract they hand you and their website is not helpful AT ALL for figuring out what health benefits will be like. I had to contact each HR personally and individually for like 90% of programs to get any real feel for that expense at all.
But these are the sort of real-life budgetary concerns that Medscape survey is zero helpful for.
