Judgment in parties’ divorce case, REVERSED, as trial court erred in ruling that appellant was estopped from denying obligation to support appellee’s minor child, who was not appellant’s biological or adopted child; although appellant signed application to amend child’s birth certificate to list him as her father and give her his name and he allegedly promised to take care of her and be her father, there was no evidence that his promise caused appellee to forego valuable legal right to her detriment; appellant identified child’s biological father, acknowledged that child was aware of his identity and stated that she never sought support, because he did not want anything to do with child.