AUGUSTA (AP) — More children would receive private insurance coverage for autism treatment under a bill being considered by Maine lawmakers. But the price tag it carries gives it an uncertain future in the Democrat-controlled Legislature this session.

Current law, which mandates that insurance companies provide coverage for treatment of autism spectrum disorder only for children ages 5 and under, is preventing families from getting effective, proven treatment for their children or forcing them onto Medicaid, say advocates who are pushing for the bill that would raise that age to 21.

“We’re basically boxing people into a corner,” said Nancy Cronin, executive director of the Maine Developmental Disabilities Council.

Medicaid now covers applied behavior analysis treatment — a regimen that psychiatric and medical professionals say is the most effective and promising for autistic children — if their autism is so severe that they would be institutionalized without treatment.

But families may not want to go onto Medicaid or their child may have a mild form of autism, preventing them from qualifying for the approach that teaches children skills by breaking them down into smaller skills, she said. Furthermore, many children aren’t diagnosed with autism until they’re older than 5, supporters say.

The measure, introduced by Democratic Sen. Colleen Lachowicz of Waterville, could also be a potential cost saver for the Medicaid program as some of those costs would be shifted onto private insurance, said Cathy Dionne, director of programs and administration of the Autism Society of Maine, who said she billed $860,000 to Medicaid for her son’s treatment from ages 4 to 16.

In 2012, the state paid claims for more than 5,830 residents with autism spectrum disorders, which can cause social and behavioral challenges, according to a recent report by the Department of Health and Human Services. That’s up 60 percent over five years, the report said.

But any bill that carries a cost will face an uphill battle this session as lawmakers grapple with a $119 million shortfall in the $6.3 billion, two-year budget and other financial issues.

The measure would result in higher monthly insurance premiums of nearly $1.50 per person, according to a report by the state’s Bureau of Insurance.

It would also cost the state about $742,000 a year, as the Affordable Care Act requires states to subsidize the cost of benefits mandated beyond those required under the law, the report said. Some autism treatment services will be covered under the new federal health care law, which requires insurers to treat mental health no differently than they do physical illnesses. But some companies still won’t cover applied behavior analysis, according to the bureau.

Lawmakers say they see merit in the bill but are worried about getting it through the Legislature and Republican Gov. Paul LePage, whose office declined to comment on the measure. Lawmakers are now considering the possibility of lowering the mandated age in the measure to 10 or 14 to save some costs and increase the likelihood of it getting passed.

“This is a big chunk of money,” Rep. Sharon Treat, a Democrat from Hallowell and co-chairwoman of the Insurance and Financial Services Committee, said during the hearing on the bill last week. “I’m not saying it’s not useful and not important, but perhaps a smaller chunk of money would be more likely to get funded through the appropriations process and pass the House and Senate.”

Advocates say that while they hope the state would see coverage up to age 21, they’ll see any expansion in coverage for the treatment as a victory.

“You take little bits and pieces,” Dionne said. “We’ll take what we can get.”