A bit over 30% of all doctors are involved in primary care. Factor out pediatricians and perhaps fewer than 25% deal with adults — a percentage that’s been declining in recent decades, according to experts, including the Altarum Institute, a nonprofit healthcare consulting firm.

Despite growing need, most medical students opt for higher-paying specialties, like dermatology or cardiology or urology or surgery — that means the overall percentage of generalist, primary care doctors, which is already too low in America, keeps declining.

“Will we see more shortages when it comes to underserved populations? Absolutely,” says Jean Moore, director of the School of Public Health at the State University of New York in Albany. “As we increase access, making sure we have an adequate primary care workforce is critical.”

It’s great that if you’ve been without insurance, you may well get it with Obamacare. But where do you go for a check-up or diagnosis of persistent pain? And if you’ve already got a friendly primary care doctor, what happens when she’s flooded with new patients and you have to wait weeks for an appointment?