My dad signed his ex girlfriends birth certificate and he's not her Father. He wants to know if he has any rights to her because he's on the birth certificate? She lives with her ex step dad

As far as the state is concerned, if he signed the birth certificate, he's her father. If the mother doesn't want him to see the daughter, it's going to be one hell of an uphill battle, but he does have rights. Go to your local courthouse and visit the family law clerk. They should be able to direct you on where to go to get information pertaining to your state. Good luck!

First, ANY question on law needs to include your general locale as laws vary by area. Second, in many places the parent does NOT sign the birth certificate. A birth certificate is prepared and submitted by the hospital. He may have signed an acknowledgement of paternity in which case, he would be considered the legal father unless challenged in court. As the legal father he has the same rights as any father.

However, with DNA testing such a challenge is not too difficult, depending on how long ago this happened.

Also, can you clarify the relationship here. I doubt if he signed his girlfriend's birth certificate. He may have signed her child's birth certificate. And who's step dad is who living with? The girlfriend's stepdad, the child's, who?