WASHINGTON - Three major health insurance companies have announced they will continue to provide coverage to dependent children on family plans until the age of 26 -- a popular part of the federal health care reform law of 2010 -- regardless of how the U.S. Supreme Court rules on the law’s constitutionality later this month. The announcements by United Healthcare, Aetna and Humana have put competitive pressure on other large insurance providers such as the Blue Cross Blue Shield Association, WellPoint and CIGNA, which have yet to follow suit. “The speculation is that many customers have come to expect certain measures in their policies and it’ll be hard to take those back,” Devon Harrick, a senior economist at the National Center for Policy Analysis, told Youth Today. But it remains to be seen how long insurance companies keep those provisions as part of their plans, especially if the U.S. Supreme Court strikes down the Patient Protection and Affordable Care Act (informally called “Obamacare”) or if competitors begin to offer less expensive, stripped-down policies some months down the line, Harrick cautioned. Adults between the ages of 18 and 24 experienced the greatest gains in health coverage of any age group since the passage of the law.