The paternity of the mother's husband can be challenged by only two people: the husband himself, and the child. In such cases the husband benefits from being presumed the father.
The paternity of the man who has acknowledged the child may be contested by all of the parties concerned, which includes the mother and the man who claims to be the biological father.
Consult a lawyer to find out the conditions and deadlines that you must meet to contest paternity, as well as the court responsible for the matter. (/where you must file your petition).
A paternity test may offer useful evidence in establishing or contesting parentage (blood relationship) before a court. It must meet certain criteria to be deemed valid. In particular, it must be conducted by an institute of forensic medicine or a laboratory recognised by the federal government. The tests that are available online are not admissible as evidence before the court. The individuals concerned must also give their written consent to the test.
Consult a lawyer to find out the criteria determining the validity of a paternity test.
If the court rules in favour of the petition contesting paternity, the man who had been considered the child's father up to that point ceases to be so, and also ceases to have any rights or obligations with regard to the child. If the child has the father's name, they will now take their mother's name. From this point on another man may officially acknowledge the child as his own.
Speak to a lawyer for more information on the conditions and deadlines that you must meet, or about the procedure for contesting paternity.
Federally designated laboratories authorised to establish DNA profiles (paternity tests)