There is no definitive answer. Your case may need to be addressed by a court order. You should consult with an attorney who specializes in custody issues.
18 unless the parents let the child choose.
No, the child's under-age parents are the legal guardians of the child.
No, unless the child is legally handicapped, the parents are only responsible for the child's welfare up to the age of 18. If the parents refuse to care for a child under the age of 18, they may be arrested for child neglect.
18 i think
A child can make that decision at the age of 18.
Generally, not until the child is 18.
Age 18 see link
Age 18 and also refuses to accept child support. see links below
Age 18 see link below
14 years of age
age 18 see links
Not really. The child of two married individuals is legally considered to be the child of both spouses. If the child is beyond the age at which the parents have legal responsibility for him/her, the legality of paternity is almost entirely irrelevant. If is mostly just a social/family issue. The parent can refuse to see the child, refuse to speak to the child, etc. The only remaining legal detail is writing the child out of the parents will, living will, etc., so that the child cannot make end-of-life decisions for the parent or inherit any of the parent's estate.