The participation of young adults in the health insurance marketplaces has received considerable attention. At issue is whether men and women ages 19 to 34—a group uninsured at disproportionately high rates but generally healthier than older adults—will enroll in marketplace health plans at a rate high enough to ensure the marketplaces' success. The conclusion of health insurance actuaries, health plan representatives, researchers, and federal officials invited to participate in a Commonwealth Fund meeting on the topic is that while young adult participation is important for the stability of the marketplaces and 2015 premiums, it was, and will continue to be, one of many factors that affect premiums. There is no single "right" rate of young adult participation that will guarantee success. In fact, health plan actuaries view health status for all age groups as being more important in their pricing decisions.