answer:In California, the “age of majority” meaning the age someone is legally considered an adult, is 18. If it’s illegal to do what the bio-dad did, he can expect to get arrested. As for what the charges might be, only the district attorney and the police would know what they would be. If this 17 year old is legally adopted, the bio dad has no parental rights. He has no say in anything that goes on with her, unless there’s some kind of special agreement, which is unlikely.