Why Illinois Prenups Cannot Decide Child Custody or Support

 Posted on September 22, 2025 in Family Law

A prenuptial agreement can be a powerful tool for couples who want to plan ahead for financial matters in the event of divorce. However, many Illinois couples are surprised to learn that child-related issues (the allocation of parental responsibilities, parenting time (750 ILCS 5/602.7), and child support) cannot legally be enforced in a prenuptial agreement.

Illinois law makes it clear that decisions regarding children must always be based on the best interests of the child at the time of divorce or separation, rather than on an agreement made years earlier. Understanding the limitations of a prenuptial agreement helps couples draft solid, enforceable agreements while avoiding clauses regarding children that an Illinois court will not enforce.

If you are about to be married and you have questions regarding what an Illinois prenuptial agreement can and cannot accomplish, consulting with an experienced Wheaton, IL family law attorney should be your best first step. Your attorney can guide you through the process, making sure there are no surprises or unenforceable clauses in the agreement.

What Things Can Prenuptial Agreements Address in Illinois?

Under the Illinois Uniform Premarital Agreement Act (750 ILCS 10/1), a prenuptial agreement can be used to address property division, debts, and spousal maintenance in the event of a divorce. An Illinois prenuptial agreement can specify how assets and debts acquired both before and during the marriage will be divided in the event of a divorce or death.

One party can agree to limit or waive his or her right to receive alimony from the other spouse, and the prenuptial agreement can detail how finances will be managed during the marriage, as well as how specific assets or debts will be handled. A well-written prenuptial agreement can protect premarital assets, gifts, and inheritances.

What Can a Prenuptial Agreement Not Address?  

A prenuptial agreement cannot address the following marital issues:

• The allocation of parental responsibilities (child custody)
• Parenting time
• Child support
• Household responsibilities, like who will do which chores
• Specifics regarding how children will be raised
•  Any illegal act

The courts view a child’s rights as independent and non-waivable by parents, and the best interests of the child will always take priority during the parents’ divorce. The allocation of parental responsibilities, parenting time, and child support is to be determined based on present circumstances at the time of the divorce, as well as the changing needs of the child’s health and schooling, and considering the evolution of financial resources and parental fitness.

Examples of Prenuptial Clauses That Would Not Stand Up in Court

The following are real-world examples of prenuptial clauses pertaining to children that would not stand up in court.

• A prenuptial clause that states "Mother will have full custody of children."
• Pre-determined child support, such as "The father will pay $800 per month in child support for each child, regardless of the current circumstances."
• A waiver of child support, such as "The mother agrees not to seek child support in the event of a divorce," would waive the child’s rights.
• Pre-determined allocation of parental responsibilities or parenting time, such as "The parents will share holidays equally, and each parent will have the children on alternating weekends." A clause like this does not take into consideration the best interests of the child at the time of the divorce.

Contact a DuPage County, IL Family Law Attorney

A good prenuptial agreement will focus on property, debt, and maintenance issues, without any unenforceable child-related clauses. A skilled Wheaton, IL prenuptial agreement lawyer from Mirabella, Kincaid, Frederick & Mirabella, LLC understands the law's limitations and will not include any unenforceable provisions that could create surprises or misunderstandings. MKFM Law serves our family law clients in Kane County, DuPage County, and DeKalb County. Call 630-665-7300 to schedule your initial attorney meeting.