Gender pay disparity is still prevalent even at the highest levels. When it comes to the world of medicine, male doctors make more than female doctors regardless of specialty, title, hours and a slew of other factors.

On average, male doctors make $12,000 more than female doctors. Considering the talent, education and competition involved with becoming a doctor, the gender disparity is rather surprising. Over the course of a female doctor's career, she could have lost $350,000 due to this pay difference.

The study was led by Reshma Jagsi, MD, DPhil, associate professor of radiation oncology at the University of Michigan Medical School. Researchers examined the pay of 800 doctors who, early in their career, had received highly competitive grants from the National Institutes of Health between 2000 and 2003.

Researchers believed that in this pool of highly-trained, motivated and well-educated individuals, any pay disparity would be minimal at best. For the study, the researchers interviewed the physicians as they entered the middle of their careers. The doctors filled out surveys that included questions about number of peer-reviewed publications, additional grants, leadership positions, additional degrees, race, location of practice and hours spent conducting research.

Considering all the factors that may cause a difference in pay, including the number of hours worked, specialty, title and productivity, the researchers discovered a $12,000 gap in pay between male and female doctors.

Without adjusting for all factors, the average salary for male doctors was $200,422 and $167,669 for female doctors. The reason for this large disparity was due to medical specialty as certain fields make more than others. Removing medical specialty as a factor narrowed the gap between men and women although men still made $17,874 more than women. Only after all factors were considered did researchers get the lowest pay difference of $12,001 between men and women.

Over the course of 30 years, that difference definitely adds up. The pay disparity among the doctors, who are doing similar work, is a lesson for all other areas of employment. If there could be a pay difference between men and women at the highest levels of the health world, the same may be true for other, less specialized fields.

The study was published in the Journal of the American Medical Association.