In Texas, a presumption of paternity mainly exists when a child is born during a marriage. A filing of an acknowledgment of paternity may also create a presumption of paternity when not married and the child lived with the parent for two continuous years.
A paternity test may be a useful tool to clarify paternity when appropriate, or when one has new evidence that paternity may be needed, such as an admission from the other parent that he is not the father, or when another possible parent comes forward claiming paternity. A paternity termination based on testing may be limited based on the circumstances relating to the length of time one knew or should have known, as well as the age of the child.
Texas does allow and encourages step parent adoptions when the proper legal elements are in place, including an adoption of the child with an affidavit to relinquish paternity. In order to succeed in these cases, all parties must be qualified for the adoption including the background of the adopting parent.