Helping spur demand, he said, might be the fact that unemployed men often qualify for free vasectomies under Family PACT, a California family planning program for low-income households.

On the Upper East Side of Manhattan, where the financial industry’s collapse has compressed many a household budget, Dr. Marc Goldstein says he has been performing more vasectomies than usual over the last five months.

Through most of last year, Dr. Goldstein, who directs male reproductive medicine and microsurgery at the New York-Presbyterian Hospital/Weill Cornell Medical Center, was performing about six vasectomies a month. Then, in November, the number rose to nine, where it was holding steady through the end of March.

“I’ve been in practice for 30 years, and I’ve never seen a spike like this,” Dr. Goldstein said. “Many of my clients work in finance and say they feel anxious about the expense of an added child.”

In Seattle, Dr. Charles Wilson of the Vasectomy Clinic says that in the last half-year he has performed an average of 123 of the procedures each month  13 percent above the year-earlier average. “Some come in because they are out of work and have more time on their hands to take care of medical issues,” Dr. Wilson said. “Others are afraid of losing their job and want to get their vasectomy done before they lose their health insurance.”

Unemployment was the reason Michael Swogger, 30, went to see Dr. Wilson. Mr. Swogger was laid off in January from his job as a Microsoft software test engineer. With three children and another on the way, he and his wife decided it was time for a vasectomy.

“I wanted to get this done before the insurance ran out,” Mr. Swogger said.

Meanwhile, visits to Vasectomy.com  a 10-year-old informational site that also markets doctors to patients  were up 17.5 percent in the first quarter, compared with the first three months of last year.