I'm a bit bewildered there's an entire discussion about this based on a reddit post. While the OP's circumstances may be true at his or her company, is it still universally accurate? I don't actually know the answer, but based on several articles released in the last year I would wager this discrepancy is no longer uniform for all industries:
There are still some statistics floating around that compare salaries without factoring in control variables (mostly based on generic census data), but these tend to be less accurate.
I think you have to look at this on a per industry basis. There are many industries which don't even have price negotiating. The government, unionized jobs, a lot of manual and blue collar positions just pay a certain rate for a particular job.
http://www.slate.com/articles/double_x/doublex/2011/02/she_m...
http://articles.businessinsider.com/2010-09-29/strategy/3007...
http://www.dailyfinance.com/2010/09/01/young-single-women-ea...
http://www.usatoday.com/money/workplace/2010-09-01-single-wo...
There are still some statistics floating around that compare salaries without factoring in control variables (mostly based on generic census data), but these tend to be less accurate.