My question involves paternity law for the State of: Pennsylvania

A friend, who is now 26, recently discovered the man she thought was her father (A), might in fact be her uncle.

FACTS:

- "Father A" and "Father B" are brothers. "Father B" was with the mother for almost two years when she left him for "Father A"

- Six months later, my friend was born

- She has two birth certificates, one with her mother's maiden name as her last name and one with "Father A" name as her last name. On both certificates, "Father A" is listed as the father.

- "Father A" did not marry the mother until after the 3rd child was born. After the fourth child was born, "Father A" left the mother for another. Then called child services and had the children taken from the mother.

- The mother died while children were young. And my friend was told she didn't have any other living relatives besides "Father A"

- "Father A" did get the children back, but because he was physically abusive, the children were taken away and placed in foster care again.

- "Father B" has stated he always believed my friend to be his daughter and he frequently called his brother, "Father A" to find out about the children. At no point did "Father A" ever tell him that the kids were in foster care.

- "Father A" has stated that he adopted my friend when she was 9.

- "Father B" found my friend through facebook a few days ago and told her he always believed he was her father. And that he tried to stay in contact with them, but his brother made it difficult and never told him that the children were in foster care.

Where does she go from here?? She'd like to know who her real father is, she'd like to have the name changed on the birth certificate. A push in the right direction would be greatly appreciated. I understand there might be some specific DNA test that would have to be done because the potential fathers are brothers. Is this true?