How to Prove a Parent Unfit in Child Custody Cases

By Cindy Cook DeRuyter

Updated November 28, 2018

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Courts evaluate the custody arrangement that would be in the child’s best interest when they determine who should have custody of a minor child. Unfortunately, sometimes this means that the person fighting for custody must prove that one or both of the child’s parents are not fit to care for the child.


State law governs how the courts view and decide parental custody matters. Proving that a parent is not fit to care for a child generally requires proof of abuse or neglect, or documentation of the parent’s substance abuse issues, untreated mental illness or incarceration.

Determine the Factors Your State Considers

The courts usually prefer to leave children with their parents whenever possible unless there's evidence of severe abuse, neglect or other problems that could harm the well-being of the child. It's possible, however, for the child's other parent, grandparent or another adult relative to petition the court for custody if they believe the custodial parent is not up to the job.

The first step in proving that a child’s parent is unfit is to identify the factors that your state considers. Reviewing your state's judicial websites for self-help information can be a good starting point. Generally, parental fitness is addressed in juvenile or family codes.

Gather Evidence and Obtain Documentation

Your belief that the child’s parent is unfit might be completely accurate, but the court might not come to the same conclusion if you don’t have documentation to bolster your case. When courts evaluate requests to give one parent sole custody, they can be reluctant to grant the request without strong evidence that doing so would be in the child’s best interest.

The evidence you need depends on the reason you're petitioning the court for custody, but might include medical records and documentation of physical or psychological abuse or records showing that the parent has a substance abuse problem or mental health issues that are not being treated effectively. The court might order a medical or mental health evaluation for your child, which can help provide information to bolster your case.

Keep Your Arguments Factual in Nature

In most cases, courts seek to maintain the parent/child relationship when making custody determinations. Even if you believe the child’s parent is unfit to have custody, try not to disparage him in your arguments. Instead, your arguments and comments should be based on the unbiased facts that support your position. Focus on how awarding you sole custody will help the child’s physical and mental well-being. If you believe the parent should not be awarded any visitation time or should have only supervised visitation time, it is important to establish that through facts and evidence.

Read More: How to Prove a Parent Unfit in Child Custody Cases

Consider Getting Legal Help

Navigating family law courts and the required forms and making compelling arguments for sole custody of a minor child can be challenging. Working with an attorney can help ensure your child’s rights and best interests are protected. Even if you think you cannot afford to hire an attorney, help may be available through pro bono resources in your state.