Every parent has a duty under the law to provide financial assistance to his minor children. This responsibility starts from the moment a child is born or adopted and does not terminate until the child is emancipated, usually when she reaches the age of majority. The duty parents owe to legally adopted children is the same as that owed to biological children.
Enforcement of Duty
Most states take an active role in enforcing a parent's legal obligation to support his kids. While the identity of a child's biological mother is rarely in question, it is more difficult to determine a child's father with certainty. A man married to a woman who gives birth is presumed by law to be the father of the child. If a married man wishes to disprove paternity, or a single mother wishes to identify the child's biological father, DNA tests can establish or negate paternity.
No Legal Duty
Adults do not owe a legal duty to pay child support for children who are not their biological children unless they have formally adopted them. Stepchildren are a good example. Many states now impose a duty on a stepparent to support his stepchildren during his marriage if he assumed them into his family. However, no state requires a stepparent to continue to support the stepchildren after he divorces their mother.
Child Support Agreement
On the other hand, no law prevents an adult from agreeing to pay child support for children he does not owe a legal duty to support. If a stepparent wishes to provide financial support for his stepchildren, he can include a provision for support in his divorce settlement agreement with the children's mother. Once the judge enters the order, the mother can count on receiving child support payments according to that agreement.