My birth mom signed the adoption for an open adoption but she got in a fight with my birth dad and told him that I wasn't hyis daughter (
Even though I was) and now he doesn't want anything to do with me. How do I prove to him that I'm his daughter?

DNA
Orchid Cellmark DNA Paternity Testing Laboratory Accreditations (http://www.orchidcellmark.com/about/accreditations.html)

Thanks :)

Are you 18?

If not, then YOU can do nothing. Your adoptive parents would have to--and they may have no reason to, except for medical information.

Why do YOU want to reach him?

If you are in contract with the bio dad, ask him to do a DNA test.

Since you were adopted out there is not even any legal way to prove it.

But legally if he accepted you as his child, and signed the adoption papers he was, but after being adopted he is no longer legally your father

I just want to reach him because it would be really nice to know him