If a person fails to challenge paternity within this period, he can lose all rights to do so at a later date. This is especially true if he acts as the child’s father in the meantime (living with the mother and child, helping to raise the child, etc.). In situations such as this, some courts have refused to even consider DNA evidence, on the grounds that a successful paternity challenge would not be in the best interests of the child.
Avoiding this situation is sometimes difficult, from an emotional and practical standpoint. If someone suspects that he is not the father of a child, the best way for him to avoid this is to refuse to put his name on the birth certificate, and to insist on a paternity test. Of course, this could strain whatever relationship exists with the mother, as it implies a suspicion that she has been unfaithful. Still, it is one of the most effective ways to avoid being the legal father of someone else’s child.