Learn which factors courts weigh in best-interest custody decisions, why state lists differ, and what counts less than parents expect.
Best for the Children Editorial·8 min read·April 14, 2026·Updated October 25, 2026
You've read the phrase "the best interest of the child" in a court notice or a lawyer's email and wondered what a judge really means by it. There is no single national checklist. Each state writes its own. Most of those lists still ask the same core questions: who the child is bonded to, how stable each home is, how healthy everyone is, what the child wants, and whether the child is safe. Some things, like parental wealth and claims of "parental alienation syndrome," count for far less than many parents expect.
Before any factor is weighed, a court has to have the power to hear the case. Under the Uniform Child Custody Jurisdiction and Enforcement Act (UCCJEA), the child's "home state" has exclusive initial jurisdiction. That is the state where the child lived with a parent for at least six consecutive months before the case was filed. For a baby younger than six months, it is the state where the child has lived since birth. This matters because the factors that follow differ from state to state. If you recently moved, the state you left may still be the one deciding.
Many state lists trace back to Section 402 of the Uniform Marriage and Divorce Act. It tells courts to decide custody by the child's best interest and to weigh:
States have built on that base in different ways. Michigan's Child Custody Act (MCL 722.23) lists 12 lettered factors, (a) through (l). They include emotional ties, each parent's capacity to give guidance, the stability of the home, moral fitness, health, the child's home and school record, the child's reasonable preference, each parent's willingness to encourage the child's relationship with the other parent, and domestic violence. Florida's statute, § 61.13(3), runs to roughly 20 factors. It also starts from a rebuttable presumption that equal time-sharing is in the child's best interest.
Across all these differences, the federal Child Welfare Information Gateway reports a common thread in state laws. The child's health, safety, and permanence come first. The sections below follow that order of importance.
When there is evidence of domestic violence, the weighing changes. In California, Family Code § 3044 creates a mandatory rebuttable presumption that giving sole or joint custody, physical or legal, to a parent who committed domestic violence in the previous five years is harmful to the child. That parent must overcome the presumption. The other parent does not have to prove harm again.
At the federal level, Kayden's Law was part of the 2022 reauthorization of the Violence Against Women Act. It pushes custody courts to put child safety first, to hold evidentiary hearings when abuse is alleged, and to limit court-ordered "reunification" programs that lack proven results.
Safety also limits how other factors can be used against a parent. Michigan's "willingness to facilitate" factor might seem to penalize a parent who keeps the child away from the other parent. The statute says a court may not hold that against a parent who took reasonable steps to protect themselves or the child from domestic violence or sexual assault.
Once safety is settled, much of a custody decision turns on continuity: which relationships and routines the child depends on. The emotional bond with each parent and the child's adjustment to home, school, and community both appear in the Uniform Act and in Michigan's list.
Siblings get special weight. Courts strongly prefer to keep brothers and sisters together because they give each other stability and emotional support. A parent who wants "split custody," with siblings living in different homes, carries the burden of showing why separating them is better for the children.
Children's wishes count, but rarely decide the case alone, and states set different age thresholds.
The mental and physical health of every person in the household is a standard factor. A diagnosis by itself is usually not the issue. What matters is how a condition affects caregiving.
This is especially true when a parent has a substance use disorder. In general, courts tend to ask whether the substance use actually impairs the parent's ability to parent or puts the child at risk. Verified participation in treatment can count in a parent's favor. Anyone looking for treatment can call SAMHSA's National Helpline at 1-800-662-4357 for referrals.
Money. A higher income does not win custody. In Burchard v. Garay (1986), the California Supreme Court held that trial courts may not base custody on the parents' relative wealth. The court reasoned that child support exists to make up for financial differences between households.
"Parental Alienation Syndrome." Accusations that one parent turned a child against the other are common in contested cases. But "parental alienation syndrome" is not a recognized mental disorder in the DSM-5 or the DSM-5-TR. In 2023, the UN Special Rapporteur on violence against women and girls issued report A/HRC/53/36. It urged justice systems to stop using parental alienation "pseudo-concepts," which the report found are used to discredit allegations of domestic violence and abuse. Kayden's Law limits on unproven reunification programs point in the same direction. A court can still look at real behavior, such as one parent blocking contact without a safety reason. It should not treat the label as a diagnosis.
For Native American children, federal law shapes what "best interest" means. The Indian Child Welfare Act of 1978 (ICWA) reflects Congress's judgment that keeping an Indian child connected to their tribe, culture, and extended family serves the child's best interests. In Haaland v. Brackeen (2023), the U.S. Supreme Court upheld the law.
Judges often appoint a psychologist to evaluate the family when the factors are disputed. The American Psychological Association's Guidelines for Child Custody Evaluations in Family Law Proceedings direct evaluators to focus on the child's best interests and to use evidence-based assessment. The guidelines also treat this forensic role as separate from therapy. An evaluator is assessing the family for the court, not treating anyone, and a parent's own therapist is generally not the right person for the job.
The phrase "best interest" also appears in decisions for adults who can no longer decide for themselves, but there it plays a smaller role. Under the Uniform Health Care Decisions Act, a surrogate making medical decisions must first use substituted judgment, meaning they decide as the patient would have based on the patient's known wishes and values. "Best interest" applies only when those wishes are unknown.
The Uniform Guardianship, Conservatorship, and Other Protective Arrangements Act works the same way. Guardians and conservators must first honor the person's known values and autonomy, and they turn to a best-interest analysis only as a fallback.
For children, the court decides what is best. For adults, the law asks first what the person would have wanted.
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