This varies from state to state.
step 1 for the bio father would be to sue for paternity; if he does so, he will establish his parental rights and may be responsible for child support as well as have visitation rights, or even be able to sue for custody.
If a father finds out he is the biological father of a child, he has as many rights to the child as the mother does. He can take the mother to court for custody or to set up a parenting plan.
Perhaps, but the better course would be to obtain a court order that reflects reality - i.e., one that finds the biological father to be the legal father. Signing over one's rights will not erase the presumption of paternity that was created by the marriage, and will not terminate any support obligations.
A biological parent is automatically the legal guardian of his or her minor child unless they voluntarily relinquish parental rights or the court terminates those rights to their child. Temporary custodial/visitation/support issues are decided at the time divorce papers are filed, the permanent decisions are finalized at the time the divorce decree is granted.
The process to get the birth certificate changed, any custody orders and child support corrected, etc., will be different in each state. You may need to see an attorney who specializes in family law. Generally there will be petitions to family court to get everything straight. You will almost certainly need an affidavit signed by both 'fathers' and DNA testing to prove who is (and isn't) father.
The law is almost universal in granting sole custodial rights to an unwed mother. This however does not mean that once the biological father has established paternity (usually required by DNA testing) he cannot petition for visitation and custodial rights. This of course will also subject him to the state laws pertaining to child support and in some cases adequate medical coverage for the child. When the biological father is a minor his financial responsibilities will generally be waived until he reaches the state age of majority, or to whatever extent the court finds reasonable.
he has all the rights if you put his name on the birth certificate but if not then he doesn't have any rights unless he takes you to court has a paternity and then the courts make you put his name on the birth certificate and then you need to ask for child support
If the father has already been established as the legal parent, either by appearing on the birth certificate or other legitimization as outlined by prevailing jurisdictional law, he is presumed to be the father unless proven otherwise. If no one contests his parentage and with the mother and biological father's consent if he can be located, the man may institute a legal adoption to secure his rights to the child.
If the court finds that the parent has been abusive or neglectful in the care of a minor child it can terminate all rights of said parent and after the time required under state law has expired the child can be placed for adoption. If there is not an issue as described above a biological father cannot be forced to relinquish his rights to his child/children so they become eligible for adoption either by a new spouse or other involved party.
A legal dad can sue in this instance, but it is highly unlikely that he would win. If the mother of the child knew who the father, she can be sued for paternity fraud.
Of course she can ask but she can not force him to. Only a judge can if he finds reasons for it.
In theory, yes, but unless the mother's parental rights are terminated (e.g., for neglect or abuse) this is so unlikely that it's not worth worrying about.
The answer depends on all the details of the situation including how long a period you are referring to, whether there is another adult willing to adopt the child, and, the laws of your jurisdiction regarding abandonment. You need to consult with an attorney who specializes in custody issues.