When local OB-GYN Dr. Phyllis Miller first entered private practice in 1975, haggling over her salary level with the practice's physician leaders wasn't the first thing on her mind.
"They just said, 'This is what we'll pay you,' and I said, 'That's fine with me' because it was more than I'd been paid in my life," she said.
Miller, who was the first female doctor from her hometown in Polk County, said she never felt she was paid less than her male counterparts.
"Maybe I wasn't as aggressive in demanding more," she allowed. "My perception is that women would not be as hard a bargainer as men. I think we tend to be satisfied. We don't have the need to ... be recognized and get paid more."
Researchers say salary negotiation habits could be one factor in the persistent pay gap between male and female doctors, despite the fact that one-third of U.S. physicians are women.
But that doesn't explain a new study's finding that the disparity in doctors' pay has actually widened significantly over the past decade.
Adjusting for specialty practices and hours worked per week, the gap in starting annual salaries for male and female physicians has grown from $3,600 in 1999 to $16,819 in 2008, according to the study published this month in the journal Health Affairs.
The study was based on survey responses from thousands of new doctors exiting training programs in New York.
The results were "puzzling" to researchers, who took pains to control for factors that could be affecting the results, in addition to adjusting for the fact that women tend to pursue the lower-paying primary-care fields rather than higher-paying specialties, said lead study author Anthony Lo Sasso, professor at the School of Public Health at the University of Illinois at Chicago.
"We tried everything we could to sort of explain the effect. ... We tried to come up with cost-of-living adjusted salaries and [the disparity] didn't even budge," he said.
Even more confounding, over the study period, a larger proportion of female doctors have migrated from primary care to more lucrative specialties, Lo Sasso said.
About 49 percent of women were in primary-care fields in 1999, compared to 33.9 percent in 2008. The proportion of men entering primary care was stable over that period, the study said.
Dr. Laura Witherspoon, a breast surgeon with University Surgical Associates in Chattanooga, said she was disheartened to hear that so many women seem to be accepting unequal salaries.
"I don't know what they're doing," she said. "It is kind of disappointing to hear that, unless there are other reasons behind it."
She suggested that, instead of pushing for higher pay, new female doctors could be negotiating non-financial benefits such as maternity leave, which most private practices do not provide.
Women may now have more leverage in making those kinds of demands since they make up a greater portion of the work force, Lo Sasso agreed. Employers now may be more willing to offer nonfinancial benefits such as flexible work schedules or exemption from late-night on-call responsibilities.
"Maybe over time [there has been] this gradual trend toward women essentially making trade-offs and being able to make trade-offs," he said. "It's becoming more important for recruiting that employers offer these nonpecuniary amenities."
But Chattanooga family medicine specialist Dr. Teresa Bays-den didn't believe that could account for such a huge disparity. She is also medical director of corporate health for Mohawk Industries in Dalton, Ga.
"I think that's probably not the case. I think [women are] just taking lower salaries," she said. "Those kind of disparities have always disturbed me and they continue to be a problem, even in a professional field."
Dr. Cherise Felix, who finished her OB-GYN residency at Erlanger hospital in 2008, said her first employer at a hospital outside Nashville offered an initial salary that seemed generous. She accepted it without negotiating.
"It was just huge for me to be making money like that," she said.
A few months later, she learned that a male colleague from her same residency class was earning $20,000 more at a hospital just 30 miles away, where demand for OB-GYN specialists was actually lower.
"Looking back now, I think I probably would have been worth more," she said. "I just didn't know enough at the time."
Witherspoon didn't discount the role of discrimination on the part of employers, who might hesitate to hire a woman, worrying that she might focus on starting a family rather than her career.
"I've heard people voice that. 'Why do I want to hire a 30-year-old woman who just got out of training, because the next thing she's going to do is have kids?'" she said. "But I doubt that it's really all that prevalent. I'm not sure I buy that either."
DISPARITIES ACROSS THE BOARD
The wage disparity in medicine is echoed in other fields, where women still face lower pay, nearly 50 years after the passage of the Equal Pay Act.
In the legal field, female equity partners earn $66,000 less than their male counterparts, according to a study released in July 2010 by the Minority Corporate Counsel Association and the Project for Attorney Retention.
U.S. Census data shows that, in 2009, the earnings of women working full time were 77 percent of that of their male counterparts.
Even today, women face barriers to attaining promotions in medicine, as in other fields, said Miller, who has been a trailblazer among female doctors. She was the first female chief of staff at Erlanger and the first female president of both the Tennessee Medical Association and the Chattanooga and Hamilton County Medical Society.
"The glass ceiling still very much exists [with] women not being promoted to the higher leadership positions as easily as men," Miller said. "I, at least, felt that I had to just work a little harder to get equal recognition.
"Some of that is self-imposed. You work a little harder to prove yourself, which to me is fine because you're just better at what you do if you work harder at it."