THURSDAY, Feb. 3 (HealthDay News) -- The average starting salary for a female physician in 2008 was $16,819 less than a male physician, a huge increase from the $3,600 gap in 1999, finds a new U.S. study.

The reason for this large difference isn't known because it isn't explained by gender differences in choice of specialty, practice type or working hours, the researchers said.

The study authors analyzed survey data from 4,918 male physicians and 3,315 female physicians exiting training programs in New York State, which has more residency programs and resident physicians than any other state.

In 1999, average salaries for new doctors were $151,600 for women and $173,400 for men -- a 12.5 percent difference. In 2008, the averages were $174,000 for women and $209,300 for men -- a nearly 17 percent difference, the investigators found.

Female physicians had lower starting salaries in nearly all medical specialties. For example, female heart surgeons made $27,103 less on average than males, female otolaryngologists made $32,207 less than males, and female pulmonary disease specialists made $44,320 less than males, according to the report.

The findings, published in the February issue of the journal Health Affairs, are significant because women account for nearly half of all U.S. medical students and are expected to account for about one-third of all practicing doctors at the beginning of this coming decade, said the researchers.

"It is not surprising to say that women physicians make less than male physicians because women traditionally choose lower-paying jobs in primary care fields or they choose to work fewer hours," study author Anthony Lo Sasso, a professor and senior research scientist at the University of Illinois at Chicago School of Public Health, said in a journal news release.

"What is surprising is that even when we account for specialty and hours and other factors, we see this growing, unexplained gap in starting salary. The same gap exists for women in primary care as it does in specialty fields," he added.

The large gender gap in starting salaries may have something to do with female physicians negotiating greater flexibility and family-friendly benefits, such as not being on-call after certain hours, Lo Sasso suggested.

"It may be that lifestyle factors are increasingly important to newer physicians. It could be that women in particular want to have more of a lifestyle balance in their medical careers," he said.

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