That is the ENTIRE point. They don't, and there ISN'T any reason for them not to.
Will Gaston doesn't seem to have a child fitting the description that he has publicized. His name was removed from Melissa's birth certificate soon after the DNA results were in.
Gastons don't address this directly. They only state that the DNA tests were done just prior to the parental rights termination trial. On the day of the trial Gastons were presented evidence that they claim they did not have time to prepare for. On that same day the court terminated any biological rights that Gaston may have had. Melissa was already a ward of the court and had been since 1991. For the apx. one year that Melissa lived with Gaston he still had no legal custody of her, he had a service agreement with social services to maintain the child.
Gaston was AWOL the first 4-5 years of Meliss'a life and only had a biological claim to the child because the diagnosed schizophrenic mother put his name on the birth certificate. Melissa's birth certificate was corrected soon after the termination hearing. If you go back over the Gaston statements you will not find any claim made by him that Melissa is his biological daughter.