This applies to female nurses /chaperones in the room as well as the gender of the doctor. Basic human psychology, and biology demonstrate that men are stimulated visually quite a bit more than women....but bottom line is that your doctor is a human being who experiences sexual thoughts on a daily basis. There is no magic on / off button as is often argued. Lustful thoughts in the exam room cannot and are not eliminated from a doctor's mind before, after, or during an exam. So in the case of a female turned on by female breasts and genitals....there is no difference. The main difference is that men , by nature, tend to dwell on sexual thoughts more often, and those thoughts are influenced heavily by visual stimulation.
The thing than can be controlled, and I often think this is what folks are trying to argue...is the control of improper behavior. Having been in the exam room many times I've noticed a few quirks. Male doctors will often work very hard to divert the outward appearance of their sexual thoughts. For instance looking away from the breasts or genitals unless absolutely necessary during an exam. It's blatantly obvious. They have a system in place to curb their behavior Female doctors, lesbian or not, are not at all this contrived in general and there is definitely a common theme, more of an emotional response, to a female patient they find attractive in some way.
I could go on with this topic for hours and have had much intelligent discussion on all this outside of the play mentality. In the course of normal daily routine a female is going to be well aware of men - mechanics, office workers, plumbers, strangers on the street....who give her the look....let their eyes wander into a stare at her breasts....etc. There are of course women checking her out as well.....i's not as obvious. Now she knows damn good and well that Joe the mechanic is checking her out...but she drops off the car, picks it back up, maybe even is flattered if Joe happens to be attractive to her. But in the doctor's office...."Dr Joe" actually gets to put a hand on that breast and a whole lot more. Surrounded by the whole social aspect that forms one's fears and opinions, she finds herself in conflict with the male doctor but safe with the female. An odd bit of psychology at work. She should be less in fear of the male doctor who admits he has lustful thoughts and works to control his outwards behavior than the one ...regardless of gender...who so proudly claims to have the magical on / off switch.