Frequently nobody mentions or gives attention to a fourth element that is always a factor to be considered.
Most states protect the legal rights of the biological father in any adoption procedure.
A pregnant woman may be able to do whatever she wants with her unborn child. Even if she decides she wants to have an abortion, she may be able to do this without the birthfather's, or anyone else's, permission. Once the child is born, however, the laws of our states give certain rights to both the biological mother and the biological father. However, if he doesn't want to be involved, has left the area, denies he is the father, etc, the birthmother may still be able to place the child with an adopting family. Most state laws say, at minimum, he must be notified if the birthmother is placing their child for adoption.