I certainly agree with you that we need to compare apples with apples. I followed up by reading the Forbes article.

1. I didn’t see a link to the study in the post (although I may have just overlooked it). The description of what the study contains is based therefore based solely on the interpretation of the writer.
2. The writer was an college intern at the time majoring in history and sociology. Without a link, I don’t have a huge amount of confidence in an undergraduate’s interpretation of a study, particularly when it's outside of the undergraduate’s area of expertise.
3. Unless I’ve incorrectly read the post, the study didn’t allow for locations or number of patients seen by the doctors. I think there was a good-faith attempt to compare apples with apples, but there were some omissions as well. Of course, given that the pay difference was less than 10 percent, the omissions would have been relatively small.
4. The author of the study said there wasn’t conscious bias by employers. The author appears to state that a major cause for the pay discrepancy is that women don’t negotiate as well. There may be cultural reasons for the difference in negotiation skills, but that’s not the employer’s fault.
5. The study’s author’s solution appears to be standardized processes for determining salaries. I’m not sure what this means, but I assume it implies some sort of regulatory control over salaries.

While it was certainly interesting to read the Forbes post and I’m glad that you pointed it out, I certainly wouldn’t treat it as authoritative.