WASHINGTON — EVERY year the National Institutes of Health receives almost $30 billion in federal funds to invest in biomedical research. The bulk of that money goes to researchers who are in many cases esteemed in their fields — but also, in many cases, beyond the age when most scientists make their most important contributions to their fields.

A study for the National Bureau of Economic Research from 2005 examined the age at which over 2,000 Nobel Prize winners and other notable scientists in the 20th century came up with the idea that led to their breakthrough. Most were between 35 and 39. Yet the median age of first-time recipients of R01 grants, the most common and sought-after form of N.I.H. funding, is 42, while the median age of all recipients is 52. More people over 65 are funded with research grants than those under age 35.

As a physician who conducted N.I.H.-funded research before entering politics, I saw firsthand how the most innovative thinking frequently came from younger scientists. The N.I.H. is likewise aware of the disparity; its director, Francis S. Collins, has spoken out about the folly of not investing in young scientists, and his organization has taken some small steps to target younger researchers. As a result, the average age of first-time grant recipients has stopped rising.

However, the problem still exists, and the N.I.H. does not have a serious plan to fix it.

Some advocates for the N.I.H. claim that if you just give it more money, the funds available to young researchers will grow, and the problem will go away. But history shows otherwise. Increases provided in fiscal years 1999 to 2003 doubled the N.I.H. budget, from $13.6 billion to $27.1 billion, and yet the percentage of grants going to first-time recipients under 36 actually dropped, to 1.3 percent from 5 percent. Nor did their share grow after the American Recovery and Reinvestment Act of 2009 gave the N.I.H. a temporary influx of funds.