This phrasing was an exaggeration, said Gerald Kominski, senior fellow at the University of California, Los Angeles Center for Health Policy Research – although not too far off.

Obama signed the Affordable Care Act March 23, 2010, Kominski said, and the provision to allow young people under 26 to stay on their parents’ health insurance was set to take effect six months later, on Sept. 23, 2010. On that date, insurance companies that offered dependent health benefits had to expand those benefits to adult children up to age 26, he said. 

Syndicated on Politifact, Austin American Statesman, among others.