A few of the more incredulous questions she has fielded: “Why would you ruin a perfectly good life by running for Senate?” “Are you off your medication?” “I know you’re used to dealing with small brains, but what about no brains?”

With a few exceptions, these physician legislators and candidates — there are three dozen of them — are much alike: deeply conservative, mostly male, and practicing in the specialty fields in which costs and pay have soared in recent years. Dr. Wehby fits their profile in all but gender, though Republicans say that having a female candidate is an added advantage in Oregon.

Senator Rand Paul, Republican of Kentucky and an ophthalmologist, is seen as a serious contender for his party’s presidential nomination in 2016. Candidates for the Senate this year include an obstetrician in North Carolina, a radiologist in Kansas, a liver disease specialist in Louisiana, and two other doctors in Georgia — all of them Republicans.

At least 26 more physicians are running for the House, some for re-election. In all, 20 people with medical degrees serve in Congress today, 17 in the House and three in the Senate, a number that has doubled over the last decade, according to the American Medical Association. (By contrast, a Johns Hopkins University study found that from 1960 to 2004, only 25 physicians served in either the House or the Senate.)

Why are so many physicians willing to trade their white coats — not to mention the autonomy, respect and high salary — for a job that can be so frustrating that it is now sending one veteran politician after another into retirement?