What would I be entitled to if I was undoubtedly discriminated against in a job interview?

I interviewed with a former employer or mine (I left on great terms several years ago) for the same position I held in the past. I was told in the phone interview that they are looking to fill the role with a female in an effort to diversify their team. I was shocked as I was interviewing for a Recruiting/HR role and this was told to me by someone on their HR team. I even followed up with an email stating that I'm still interested and mentioned that I know they're looking for a female, but if they can't find one that is qualified to please keep me in mind. He (the recruiter) acknowledged that they're working on diversity within that team, but they would keep me in mind for future openings. I'd like to go after them for this. Please advise.