Former girlfriend said she was pregnant 20 years ago for you did not tell until now what are your rights?

Former girlfriend said she was pregnant 20 years ago for you did not tell until now what are your rights?
Any child is 20 years old and an adult in virtually every country (bar two or three) in the world. You have no rights over them whatsoever; the upside is you have no responsibility at all either, since she never told you until well after the fact and also has no proof.