BOSTON — James and Chelsea Rosato don't know what caused the death of their 8-year-old son, J.J., who passed away in his sleep nearly two years ago. But they say routine medical screenings might have detected a problem.

In their search for answers, the Danvers couple helped write a proposed law requiring insurers to pay for routine echocardiograms and concussion analysis for children between ages 5 and 18. The bill was heard by a legislative committee Tuesday.

"Why not be proactive and have kids tested before something happens?" James Rosato told members of the Joint Committee on Financial Services, as he and his wife fought back tears. "I don't want other parents to have to go through this."

Rep. Ted Speliotis, D-Danvers, the bill's primary sponsor, said regular screenings could detect childhood illnesses and concussions. He thinks insurance coverage should be mandatory, leaving the question of whether to test a child up to the parents.

"It's a preventative measure, whether it's every year or every two years," he said. "This is something that clearly isn't being done now."

Speliotis, who fought more than 12 years to get insurance coverage for long-term Lyme disease treatment, said he knows the measure faces an uphill battle as lawmakers struggle to contain rising health care costs.

Sen. Joan Lovely, D-Salem, said requiring insurers to cover the tests would assuredly result in more kids being evaluated.

"Currently these tests are typically not covered by health insurance," she said. "This bill would improve access to these critical tests."

James "J.J." Rosato, a third-grader at Great Oak Elementary School in Danvers, passed away in December 2015 after playing hockey at Boston University during a friend's birthday party. An autopsy and extensive post-mortem tests failed to determine the cause of death, his parents said.

“Almost two years later, they’re still testing,” James Rosato said at Tuesday's hearing, pounding on the table. "There's no word — nothing."

Since their son's death, the Rosatos have gotten involved with a national nonprofit, Sudden Unexplained Death in Childhood Foundation, which provides support for grieving parents and pushes for more federal funding for research.

An estimated 400 children ages 1 to 18 die each year with no cause found, despite an autopsy and investigation, according to the Centers for Disease Control and Prevention.

James Rosato said regular screening should be mandatory when school-age kids play football, hockey and other contact sports. He puts his two other children through screening every six months.

"There should be better screening ... allowing parents and insurance companies to catch it in time," he said. "A stethoscope doesn't hear everything."

But the proposal could drive up health care spending, according to the Massachusetts Association of Health Plans.

Eric Linzer, the group’s spokesman, points out that Massachusetts has more health care mandates than most states, burdening small businesses more than larger, self-insured companies.

"That ultimately increases costs for employers at a time when they're grappling with rising health care costs,” he said.

A spokesman for the state Center for Health Information and Analysis said it hasn’t reviewed the bill to estimate how much it would cost.

Christian M. Wade covers the Massachusetts Statehouse for North of Boston Media Group’s newspapers and websites. Email him at cwade@cnhi.com.