HARRISBURG - Parents of autistic children would be able to pay for behavioral therapy and related services with private health insurance starting next year under legislation that strikes a compromise between the insurance industry and advocates for the disabled.

The House of Representatives unanimously approved the measure on Tuesday. It would also require insurers to cover colorectal screenings and would give the state Insurance Department the power to approve the proposed merger of Pennsylvania's two largest insurance companies, Highmark Inc. and Independence Blue Cross.

The Senate last night approved the bill, 49-1, sending it to Gov. Rendell, who said he would sign it. Voting no was Sen. John Eichelberger (R., Blair).

Autism is a complex developmental disorder that impairs one's ability to communicate and interact with others. Its severity varies.

"It's so critical for these families . . . when you live with the tragedy of people rejecting their kids as if they don't have value, because we don't provide the services that are necessary to their developmental achievement," said House Speaker Dennis O'Brien (R., Phila.), a longtime advocate whose 22-year-old nephew has autism.

The bill would require insurers to provide up to $36,000 in coverage initially for autism therapy for people under 21; the state's Medicaid program would pay for any costs that exceed that cap. Businesses with 51 or more employees would have to offer the coverage starting next July 1, while smaller businesses would be exempt.

Nearly two dozen other states have laws mandating some level of autism insurance coverage.

Pennsylvania officials have estimated that more than 21,000 children ages of 2 to 20 have autism and related disorders. About 13,800 of them are insured under the state's Medicaid program.

But Medicaid coverage has significant shortcomings, according to a recent analysis.

Insurance companies argued that a mandate would be too expensive. But they ultimately accepted a version of the bill that O'Brien said would preserve services for children receiving Medicaid when their coverage switches to a private insurer.

The legislation is expected to save the Medicaid program $13 million in the 2009-10 fiscal year.