The Association of American Medical Colleges estimates that in 2015 the country will have 62,900 fewer doctors than needed. And that number will more than double by 2025, as the expansion of insurance coverage and the aging of baby boomers drive up demand for care. Even without the health care law, the shortfall of doctors in 2025 would still exceed 100,000.

Health experts, including many who support the law, say there is little that the government or the medical profession will be able to do to close the gap by 2014, when the law begins extending coverage to about 30 million Americans. It typically takes a decade to train a doctor.

“We have a shortage of every kind of doctor, except for plastic surgeons and dermatologists,” said Dr. G. Richard Olds, the dean of the new medical school at the University of California, Riverside, founded in part to address the region’s doctor shortage. “We’ll have a 5,000-physician shortage in 10 years, no matter what anybody does.”

Experts describe a doctor shortage as an “invisible problem.” Patients still get care, but the process is often slow and difficult.