In California, the terms “paternity” and “parentage” and “parental relationship” are used interchangeably. In order to establish paternity, either the parents of a child or the courts must ascertain who the father of a kid is. In certain cases, the law assumes the identity of the father, including:
When a child is born during a marriage, the mother’s husband is presumed to be the child’s father. When a man has lived with the child and mother in a family-like manner and has demonstrated a commitment to the child, he is presumed to be the child’s father, even if he is not the child’s biological father.
In the absence of these two conditions, paternity must be demonstrated.
Read more here: Paternity in California