About Parental Rights?

My Cousin is marrying a man that already has a son from a a prior relationship the child is almost 13.My cousin's boyfriend,although I do not agree with this.Wants to sign over his rights to his son.I feel alot of this has to do with the fact that he does not wnat to pay child support for this child,especially now that he and my Cousin have a newborn.He is under the impression that if he signs his rights over he will no longer have to pay support.I am trying to tell him that the courts could still force him to pay support.We live in Maryland,and I am not sure about the laws here when it comes to this.