Although an Ohio man may be a child's biological father, if he was unmarried to the child's mother at the time the child was born, he will need to establish his paternity of the child in order to establish his parental rights. Once paternity has been established, the father may then pursue custody and visitation rights.
In some cases, a woman may have falsely named another man as the child's father. In that case, the biological father will need to file a challenge to the other man's presumed paternity by filing a motion in court. The father and the child will then be tested genetically in order to determine paternity of the child.
In other cases, a man may have fathered a child with a woman who was married to another man at the time. When a man is married at the time his wife is pregnant or gives birth, courts will presume the husband to be the father. The biological father and the husband may both wish to challenge the presumption in court in order to establish the biological father's paternity of the child.
Fatherhood comes with fundamentally important constitutional rights and responsibilities. Fathers are able to pursue and receive visitation with their child and possibly seek and receive primary custody. In this way, fathers and their children can develop lifelong relationships and strong bonds. By establishing parental rights through paternity and subsequent motions, fathers may then receive parenting time. While fathers may also be required to pay child support, they may be the recipient of child support instead, depending on the relative incomes of the parties and the resulting custody orders. Child support is a small price to pay in order to enjoy the lasting and joyful relationship a father may enjoy with his child.
Source: Findlaw, "Challenging Paternity", December 04, 2014