Interrogated for cheating based on discrimination a potential lawsuit?
As in the comments, there is important ambiguity in your question.
Granting your account of the situation, you were certainly treated prejudicially and unfairly. Even if you'd not been a recent-mom, doing a wonderful project does often trigger suspicion in any case, and, yes, all the worse if the people in charge have negative expectations of recent moms, or women in general, or...
As in the comments: what do you want out of this situation? Did the people in that interview concede that you did not cheat? And at that point did they apologize? Is this on-going?
For example, in my own experience, never in a million years will people in power who behave badly acknowledge this. Endless rationalizations about how it's either no one's fault, or society's fault, or maybe your own fault.
Still, yes, I agree, anger is justified. Such situations are grotesque, and have a big impact on people.
And, still, what would be the goal of a lawsuit? An apology? Monetary compensation? (The latter would probably cost more in lawyer fees than what you'd get...)
Again, as in the comments, think what you want out of this situation, apart from being justifiably angry with idiots. Taking idiots to court is an expensive and unrewarding hobby... even if sometimes historically necessary.