How can a father sign his child's birth certificate in the state of Atlanta Georgia with out the mother being present? How can the do this if the mother doesn't have custody of her child?

It depends. Was the baby formally adopted? What are the circumstances?

First not enough info provided, who has custody if the mother does not, is this legal custody, if so was the child adopted or taken away by CPS ?

A father has rights, and should have been contacted before child could be adopted. Please explain this a lot more