In Wisconsin, paternity – the legal relationship between a father and child – has to be established before the courts can enforce a father’s rights or obligations. In many cases, paternity is assumed. For example, if two married people have a child, the state of Wisconsin assumes that the husband is the child’s father. However, when unmarried people have a child, the court won’t assume; you must establish paternity first.
Wisconsin Paternity Statutes

There are two ways to establish paternity under Wisconsin law:
- Acknowledging paternity
- Asking a court to establish paternity
Here’s a closer look at each.
Acknowledging Paternity in Wisconsin
The simplest way to establish paternity in Wisconsin is for both parents to sign a statement that affirms a man is a child’s biological father. You can then file the statement with the Wisconsin state registrar. After you file the statement, either one of you can file a case asking the judge to rule on child custody, visitation and child support.
Asking a Court to Establish Paternity
If signing a statement to affirm paternity doesn’t work in your case, you and your attorney can file a petition with the court in the county where the child lives. Once the petition is filed, your attorney will have it served to the other parent – and then the court will set a hearing date. If either parent requests genetic testing, the court can order the potential father and child to do so to establish paternity.
Who Can File a Petition to Establish Paternity in Wisconsin?
The state of Wisconsin allows several people to file a petition to establish paternity, including:
- The child’s biological mother
- The child
- A male who claims to be the child’s father
- Someone who has legal or physical custody of the child
- The state of Wisconsin
- A guardian ad litem representing the child
- A grandparent, provided the parent is dependent on that grandparent
Wisconsin Child Support: Do You Need a Paternity Test?
The courts won’t enforce child support if you haven’t established paternity. If your child’s father has not signed a statement affirming his paternity, you can ask the court to rule. In some cases, the court orders genetic paternity testing.
Wisconsin Custody Laws for Unmarried Parents
In Wisconsin, custody laws for unmarried parents are the same as those married parents have to follow. The only exception is that you have to establish paternity (either by signing a statement or asking the court to rule) before the courts will enforce custody agreements, visitation and child support.
Do You Need Legal Advice on Establishing Paternity in Wisconsin?
If you need legal advice about paternity in Wisconsin, or about anything else related to child custody, visitation or child support, we can help. Call us at 414-383-6700 for your free consultation now.