The Forensic Minute January 2026 Issue: Juvenile Forensics & Adolescent Decision-Making

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Michigan’s Ruling That Redefines Youth & Justice

In April 2025, the Michigan Supreme Court held that mandatory life-without-parole sentences for 19- and 20-year-olds convicted of murder violate the state constitution. The justices concluded that imposing such punishment without considering an offender’s youth and capacity for change is “grossly disproportionate.” Notably, the court relied on scientific evidence showing that brain development continues into the early twenties, recognizing late adolescence as a distinct developmental stage. The ruling therefore sets an important precedent: neuroscience research on adolescent development can influence sentencing decisions beyond the federal juvenile cutoff of 18. By extending constitutional protections to late adolescents, the decision illustrates how courts are increasingly turning to developmental science to shape criminal sentencing.

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Late Adolescence, Neuroscience, and Sentencing Disparities

While landmark U.S. Supreme Court decisions prohibit extreme punishments such as mandatory life without parole for juveniles under 18, recognizing that adolescent brains are still developing, many legal systems continue to treat 18-, 19-, and 20-year-olds as fully mature adults. This persists despite extensive research showing that decision-making, impulse control, and risk assessment in these “emerging adults” often resemble those of younger adolescents. Until recent state court rulings, including Michigan’s, individuals in this age group routinely faced the same mandatory adult penalties as older offenders, notwithstanding a growing body of developmental science. Even when life-without-parole sentences are avoided, people who committed offenses in their teens or early adulthood frequently receive disproportionately severe punishments, with youth of color especially likely to be transferred to adult courts and subjected to harsher sentencing. The result is an enduring tension between retributive justice—punishment driven primarily by the severity of the offense—and developmentally informed justice, which accounts for maturity, culpability, and capacity for rehabilitation. Public fear of crime and tough-on-crime politics often exacerbate this divide, encouraging lawmakers to sideline adolescent neuroscience and further widening the gap between science and sentencing.

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References:

Fair and Just Prosecution. (2024, December 23). FJP urges MI Supreme Court to find mandatory life without parole sentences for emerging adults unconstitutional. https://fairandjustprosecution.org/press-releases/fjp-urges-mi-supreme-court-to-find-mandatory-life-without-parole-sentences-for-emerging-adults-unconstitutional/

National Conference of State Legislatures. (2025, June 30). Juvenile justice update | June 2025. https://www.ncsl.org/newsletter/details/juvenile-justice-update-june-2025

Poggio, M. (2025, June 27). How states are rethinking life without parole for youth. Law360. https://www.law360.com/articles/2330522/how-states-are-rethinking-life-without-parole-for-youth

Zhao, R. (2022, April). Second chances: Why Michigan should categorically prohibit the sentence of juvenile life without parole. Michigan Journal of Law Reform. https://mjlr.org/journal/second-chances-why-michigan-should-categorically-prohibit-the-sentence-of-juvenile-life-without-parole/