By Dr. Liji Thomas, MD Reviewed by Lauren Hardaker Apr 30 2026 A child’s earliest exposures may leave lasting biological signatures. This study shows how tiny layers in baby teeth can pinpoint when metals may influence brain development and behavior years later.  Study: Fetal and postnatal metal metabolism–related changes in brain function are associated with childhood behavioral deficits . Image credit: Onjira Leibe/Shutterstock.com A novel study using baby tooth biomarkers to trace metal