It's a season of joyous firsts for the founding class of the Commonwealth Medical College. Students were matched with residencies a few weeks ago and over the weekend, the students became the school's first M.D. graduates.

That's good news on a broader scale because TCMC is in the first wave of a new group of medical schools created, in part, to deal with a growing national doctor shortage. The Association of American Medical Colleges projects that the nation will have a doctor shortage of 62,900 by 2015 and up to 140,000 by 2025. Nationally, medical school enrollment is expected to result in about 5,000 more graduates a year by 2019.

But unless Congress acts to relieve a tightening bottleneck in the medical education system, the doctor shortage actually could worsen despite the growing number of medical school graduates.

After graduation from medical school, doctors serve medical residencies of up to seven years, depending upon their specialties. Medicare funds 94,000 residencies at teaching hospitals, at a cost of about $9.4 billion a year, and Medicaid funds about 10,000 more at other institutions

Now a number of factors are converging to create a shortage of medical residencies, rather than of doctors to fill them. According to the Association of American Medical Colleges, the number of graduating physicians will exceed the number of available residencies by the end of this decade. The squeeze already has begun. A record 1,097 graduates were not matched with residencies this year, a 29 percent increase over 2012.

The Balanced Budget Act of 1997 froze the number of medical residencies. But since then, the U.S. population has grown from 267.7 million to 315.7 million. People also are living longer, and older people need more health care than younger people. Next year, the Affordable Health Care Act is scheduled to be fully implemented, expanding the number of people with health insurance and, therefore, demand for medical services.

Last week Rep. Allyson Schwartz, a Pennsylvania Democrat, and Rep. Aaron Schock, an Illinois Republican, introduced a bill to increase the number of residencies by 15,000 over five years, at a cost of about $1 billion a year.

Congress should increase the number of funded residencies in accordance with demand. Prospective doctors without residencies are wasted resources. And it's more expensive to limit primary care by limiting residencies to train physicians, than to pay for the residencies.