I have a yourng mother who wants to give her child up at birth to me and my husband what is my legal grounds. She is willing ot sign all rights over

I don't know what you mean by your legal grounds.

You would be foolish to attempt this without an Attorney. Laws vary by State. You must also make every attempt to get the consent of the father.

You may need a home study.

An Attorney would make certain that the adoption would not be overturned at some point in the future.