The Affordable Care Act, passed in March 2010, requires that all health insurance providers extend coverage to adult children up until their 26th birthday. Extending coverage is required even if the adult children are married.
Certain states require that health insurance plans continue to cover children even after their 26th birthday. For example, Florida allows dependent children to remain on their parents' plan up to age 30 provided they are unmarried and childless.
As of 2010, reimbursements for health insurance premiums for adult children under the age of 27 do not count towards the parent's taxable income.
More than 9,558,504 Americans between the age of 18 and 25 were uninsured in 2008, according to the Institute for Women's Policy Research. Keeping your children on your health insurance plan through this age range helps keep them healthy through college and the first years of their career.