A more thorough explanation:

Maternity presumption is a legal concept in family law that assumes the woman who has given birth to a child is both the genetic and legal mother of the child.

For example, if a woman gives birth to a child, she is presumed to be the child's mother, even if there is no genetic testing to confirm it. This presumption can be challenged in court, but it is the default assumption.

This presumption is important because it establishes the legal relationship between a mother and her child, including rights and responsibilities such as custody, visitation, and child support.