Steve Chiotakis: I can remember when I was a lot younger, I thought I was invincible. Health problems? Me? Nah. But a study out this morning finds two out of five young people have medical debt.

From the Marketplace Health Desk at WHYY, Gregory Warner reports.

Gregory Warner: Young people are relatively healthy and cheap to insure. But when bad things happen:

Sara Collins: They have less income and less insurance coverage.

Sara Collins of the Commonwealth Group is lead author of the study released today. It found that 40 percent of young people — and over half of young women — have problems paying medical bills. Having health insurance is no guarantee against going into debt; college health plans are often limited.

Collins: A lot of these policies are really skimpy and you may not notice that it has a low lifetime benefit limit until you actually go through the benefit.

Warner: Until you have that accident.

Collins: That’s right.

Warner: Or you get pregnant.

Collins: Right.

Collins says the health care reform law is having a major effect on this age group. Half a million people under 26 have already signed up under their parents’ plans. Next year, all college health plans have to cover catastrophes, same as private insurance does now. By 2014, over seven million young people will qualify for Medicaid under new expanded rules. Whether they sign up depends on how invincible they feel.

In Philadelphia, I’m Gregory Warner for Marketplace.