In order to get a green card (permanent residency in the US) you need to undergo a medical exam. And only a few certified physicians can do this. Part of the exam they must verify your gender which apparently can be quite uncomfortable if you're a woman and your physician has a bad day. So here's a tip; find a clinic that have somebody who can do the green card exams. Use that clinic as your regular doctor and make sure to do an annual health check a few months prior to your green card exam. This way they may use some information from that annual exam as part of your green card exam so you save both time and discomfort. i don't know if this is how it's supposed to work everywhere but it worked for us.