Paternity law is a branch of family law that legally establishes parenthood. The paternity suit is usually brought by an unwed mother against the father of a child. In married couples, the husband is automatically assumed to be the biological father of any children produced in the marriage. If the husband wishes, he can contest the paternity of a child and absolve himself from legal duties to care for the child.
Paternity is established using a DNA test between the mother, father, and child in question. This is usually done with a saliva swab, but may also be done by a blood test. Once the biological father is determined, he can then be held liable for custody and child support.