Illinois Law on Parentage in Open Marriages and Non-Marital or Infidelity Claims

In Illinois, when a child is born during a marriage, both married parties are legally presumed to be the biological parents, regardless of the actual biological connection to the child. This legal presumption can create complex situations, especially in cases involving open marriages or marriages dealing with infidelity where a child may be conceived with someone outside the marriage. Illinois law, however, provides clarity on this issue through its parentage statutes, including provisions that allow non-married biological parents to assert their rights—but only under strict timeframes.

Under the Illinois Parentage Act of 2015, a child born to a married couple is presumed to be the child of both spouses. This presumption applies automatically and does not require any action from the couple to establish them as parents. Even in cases where the couple is in an open marriage or there is a concern over infidelity and the child may be biologically related to another person, the law imputes parentage to the married spouses. This legal framework aims to provide stability and certainty for the child, but it can lead to conflicts when the actual biological parent is not the spouse.

In situations involving open marriages or infidelity, the biological parent of the child—who is not one of the married parties—can still assert parentage rights. However, Illinois law places a strict time limit on when this can happen. The Illinois Parentage Act allows the biological parent (who is not married to the mother or father) to bring an action to establish parentage within two years of the child’s birth. This two-year window is crucial. After this period, the biological parent may be barred from asserting parental rights, even if they can prove biological parentage through DNA testing. The court prioritizes the best interests of the child and the legal presumption that the married couple is the child’s parent unless the biological parent acts promptly.

To challenge the presumption of parentage, the biological parent must file a parentage action within the two-year window. Courts will require proof of parentage, which typically involves DNA testing at a court-ordered, approved facility or provider. If the biological parent can prove a genetic connection to the child, the court may recognize their parental rights, potentially leading to the modification of the legal parental structure.

However, Illinois courts are also guided by the child’s best interests. This means that even if the biological parent successfully asserts their rights, the court may weigh other factors, such as the existing parental relationship between the child and the spouse of the biological mother or father. The goal is to ensure the child’s well-being, which may sometimes mean preserving the existing legal parent-child relationship despite the biological reality.

For couples in open marriages or where infidelity is a factor, understanding the implications of Illinois parentage laws is essential. Even if they agree that someone outside the marriage will be the child’s biological parent, the law will still impute parentage to both spouses unless challenged in court. This can complicate family dynamics, especially if the biological parent seeks to assert rights down the line, including parenting time or child support.

Illinois law provides a clear framework for handling parentage issues in cases involving married couples, including those in open relationships or where there are concerns of infidelity. The legal presumption that married parties are the child’s parents can be challenged, but the biological parent must act within two years of the child’s birth. The law seeks to balance biological realities with the child’s best interests, providing a pathway for non-marital parents to assert their rights while ensuring the child’s stability.

Consulting with an attorney early on can help avoid misunderstandings and ensure that all parties’ rights are protected within the bounds of Illinois law – which is presently two years.  Jennifer R. Ward of WARD FAMILY LAW, LLC is available for a consultation via email: jward@wardfamilylawchicago.com or telephone: 312-803-5838.