http://www.usatoday.com/news/nation/2007-02-20-custody-battle_x.htm
This is the story I was thinking of.
It sounds as though the child was never officially adopted; the outcome should depend upon what exact agreements were documented between the birth parents, the agency, and the guardians.
BTW, with regard to the Baby Richard case, I would suggest that men who believe a woman might be giving birth to their child and might give it up for adoption should be required to file a claim before the child is born or very soon (within, e.g. a week) after birth. In the event that the mother is not recorded as having given birth within a year of a filed claim, proof of filing would be returned to the father (in case it's needed for tort actions) and the claim would be removed from file.
If a father does not file a claim in timely fashion and the child is adopted, all fatherly claims would be forfeit. If the father does file a claim but the mother evades it (e.g. by signing into the hospital with a false name when she gives birth) the father should be able to seek civil and criminal actions against the mother, but the adoption would remain valid.
That's how I'd like to see things work. Sound better than the present mess?