My question involves paternity law for the State of: Wisconsin

My boyfriend has an 18 month old child with a woman living on the other side of the country. He is not named as the father on the birth certificate but has been financially supporting them beyond what would be required under court-ordered child support and pays for separate medical coverage for both the mother and baby. He visits the child and wants to maintain a relationship with the child. Because the baby is so young now and very attached to its mother, he hasn't hasn't sought any custody/visitation arrangements yet. As the baby gets older, he plans to make those arrangements on his own with the mother.

The situation seems to be going fine as it is now. The baby is being cared for, emotionally and financially. My boyfriend and the mother are two reasonable people who seem to be handling the situation fine without family court or lawyers. But I'm wondering if its important for my boyfriend to get his name on the baby's birth certificate and establish legal paternity for reasons he may not be considering?