Gender discrimination is often subtle and not overt. It is more difficult to prove, but not impossible. Such circumstances make it more critical that you retain a local employment law attorney to represent you in the matter to aid in determining the best method for proving that discrimination is involved and guide you in making the strongest case possible, so it can be resolved through mediation or litigation.
Normally, a complaint of discrimination must be filed with the company's HR department, unless filing a complaint would be futile, which is likely to be the case here. If that is the situation, then a charge should be filed with the state Fair Employment and Housing Commission within 300 days of the alleged discriminatory conduct.
The state and local bar associations can provide you with attorney referrals.
Here is a link to the Commission's website:
I hope you found my answer helpful, even if the law is not in your favor. I would be happy to clarify my answer if anything is not clear or you are looking for additional information. All the best to you!