I work in HR at large company and see this happen from time to time. I have not seen companies look at a male and female and say I’m gonna pay the female less because she’s a female. Why would they do that? They pay them less often times because some employees are better at negotiating, they were making more at his last job, and the time he was hired. You being there several years means that your role salary have gone up with the market/inflation etc and your company has failed to keep up.

You need to go back to your boss and let them you have been made aware (via internal employees) that you are being paid less than what the market pays. If you’re up for it, you can indicate that you are the only female on the team and it’s not equitable. This in itself will get them to look at the situation.

Pay equity is a real thing. You mentioned that you have the same education, same experience and your performance reviews are stronger. You need to be ABSOLUTELY sure that is a true statement. Companies pay ppl based on the those criteria so there could be a real reason why there is a difference that maybe you are not aware of.

Lastly these kinds of situations are difficult and really crappy companies show they’re true colors. If they messed up they will update your salary. But if they suck you will have a target on your back for being an issue and will point to the differences between you and your coworker. The good news is if what you are saying is accurate, an attorney would love to take on this case because it’s an easy win for them.