By Dr. Sanchari Sinha Dutta, Ph.D. Reviewed by Lauren Hardaker Jun 26 2026 A large California study suggests that characteristics present at birth and parental factors may help shape the risk of developing colorectal cancer before age 40, offering new clues into why rates are rising in younger adults. Study: Demographic, birth, parental characteristics, and the risk of early-onset colorectal cancer: A population-based nested case-control study in California . Image credit: Tama2u/Shutterstock.