I recently went to a Macado's, for karaoke night. When we went to enter, the lady said it would be a 2$ "Cover fee". I asked if it was for both of us (my gf and I), or total, and she said it was just for me because im male. I have since found out that this is common practice in bars, nightclubs, and other things to ensure a nice ratio of men to women. Still, it feels very sexist to charge more for a specific gender. From the research I have done, it seems to be a grey area or illegal but largely unenforced. I am in Virginia, BTW.
The most on topic sources I have found are here and here.
I have looked for questions on this site, but have not seen any (that closely relate) after going through several pages.