14 pages. Excerpt: Young adults (ages 19 to 29) are one of the largest and fastest-growing segments of the U.S. population without health insurance: 13.7 million lacked coverage in 2004, an increase of 2.5 million since 2000. Young adults often lose coverage under their parents' policies, Medicaid, or the State Children's Health Insurance Program at age 19, or when they graduate from high school or college.