Newly trained male doctors in the United States are paid on average $16 819 (£10 450; €12 350) more a year than their female colleagues, a new study has found. More discouraging is that the pay gap has widened over the past 10 years.

In 1999 female doctors received an average starting salary of $151 600 a year, 12.5% lower than the men’s salary of $173 400, shows the study published in Health Affairs (2011;30:2193-201, doi:10.1377/hlthaff.2010.0597). By 2008 the gap had widened to nearly 17%, with women being paid $174 000 and men $209 300.

The study used survey data collected between 1999 and 2008 from doctors exiting residency training programmes in New York state, which has the largest number of such programmes in the US. It focused on responses from 8233 doctors (4918 men and 3315 women) who said that they had been offered and had accepted a job where care of patients and clinical practice would be their main activity.

Anthony Lo Sasso, senior author of the study, told the BMJ that previous research attributed much of the observed difference in pay between male and female doctors to men having more senior positions, working longer hours, and being more likely to be in higher paying specialties, among other factors.

The professor of health policy and administration at the School of Public Health at the University of Illinois, Chicago, said that the study sought to neutralise those factors by focusing on the transition point to first employment. It also compared pay within medical specialties.

Professor Lo Sasso said that he was surprised to see the consistent worsening of the differential between men and women in this population of doctors who were just beginning their practice. He said that the researchers looked at alternative explanations, “but nothing could make this large and widening gap go away.”

He added, “Whatever is going on is something broad based, something affecting women regardless of specialty.” He speculated that perhaps women “are more likely to forgo some salary in order to gain some type of non-pecuniary job attribute, such as a favourable or ‘no call’ schedule.”

Responding to the findings, Eliza Chin, president of the American Medical Women’s Association, said that their ramifications were “shocking, particularly for young physicians getting their first job. We would expect in this day and age that the gender gap [in pay] would be getting smaller.”

Roberta Gebhard, who co-chairs the association’s gender equity task force, said, “We feel that gender discrimination exists at many levels in American medicine . . . Women face a hostile environment.” She said that men are disproportionately in positions to hire, fire, and promote doctors and that they are more comfortable advancing those who are most similar to themselves.

Linda Brodsky, the task force’s other co-chair, added: “Many of these young women don’t know that gender discrimination exists. They are lulled into thinking that they are getting flexibility [in hours and working conditions].” Thus they might consciously or otherwise accept a lower salary, she added.

Dr Brodsky said that many young women are not good negotiators and that when they do act tough in negotiations this creates a “dissonance to the people who are hiring them,” as they are not then fulfilling the stereotype of a caring provider.

The association is creating a web based programme to help its members become better at negotiating.