Young healthy Americans are not flocking to enroll in the Affordable Care Act in numbers that the White House had hoped to see.

New enrollment figures out this week show that 24 percent of those buying coverage are young adults in the prime age group between 18 and 34. That's the age range that the White House says needs to enroll in large numbers in order to balance the cost of coverage among older, sicker Americans.

The figure are a big improvement over the last two enrollment announcements but it's still short of the roughly 2 in 5 Americans that analysts have said are required to prevent health plans' premiums from going up.

One-third of the 2.2 million people who have enrolled so far are 55 to 64 years old. Members of this group are important for keeping insurance costs down, since they are typically healthier.

Why aren’t younger Americans enrolling in masses? Does allowing young adults to stay on their parents’ plan until 26 affect enrollment? How can the marketplace become more attractive to the young enrollees? What effect will the lack of young enrollees have in the long term?

Guests:

Dylan Roby, Assistant professor of Health Policy and Management at the UCLA School of Public Health

Yevgeniy Feyman, fellow at the Manhattan Institute