Nicastro Piscopo, APLC | Louis M. Piscopo
For a US Citizen born out of wedlock can petition his father, however, you will have to prove either a bona fide parent-child relationship existed before you turned 21 years old. A bona fide relationship is when the father has shown an active concern for the child's support, and showing of communication with the child. Also, if the child was legitimated prior to turning 18 years old, was in the legal custody of the father at the time, and is the natural/biology father of the child, then the child can petition the father.
Answer Applies to: California