That being said, there are a few specific ways to proceed with an adoption when one biological parent is out of the picture. First, it is possible to go forward without a biological parent's consent if you can prove that the absent parent has not exercised any parental rights and convince the court that it's appropriate to legally terminate that parent-child relationship. Most states' laws allow parental rights to be terminated when a parent has willfully failed to support the child or has abandoned the child for a period of time, usually a year. Generally, abandonment means that the absent parent hasn't communicated with the child or supported the child financially. If the absent parent is a father, another common way to terminate his parental rights is to show that he is not, legally speaking, the presumed father of the child.
Most states have statutes establishing who the presumed father of a child is in certain situations.
In this case, you won't have to prove that the father has abandoned the child. You simply must show that he does not meet the legal definition of presumed father. For instance, in all states, a man who is married to a woman at the time she gives birth is legally presumed to be the child's father. Another way of establishing presumed fatherhood in many states is by marrying the mother after the child has been born and being named as the father on the child's birth certificate. If you can show that the father doesn't meet any of the tests in your state for presumed fatherhood, the court may terminate his rights and allow you to proceed without his consent.