You are being way too worried about such a small and inconsequential thing. I always wear feminine underwear and I never worry about such issues. Earlier this year I had an annual check up with a dermatologist. The usual routine is I take off my shirt exposing my depilated upper body in the process and he scans my body with a special light looking for any signs of skin cancer. His nurse/assistant is always with him taking notes. This year he also asked to see my legs so I had to lower my jeans to expose them and of course I was wearing a very nice pair of pink panties. They were not see-through however. He scanned my legs without showing any sign of interest in what I was wearing and neither did his nurse. He left and I had a brief conversation with the nurse about skin care etc. and it was all very professional. No medical person would take notes on what you wear and they never would include such information on an insurance claim. Why would they. It is irrelevant and would confuse the reimbursement process. Your interaction with your doctor is private and nothing should be disclosed to your employer and of course no information is shared with anyone else including your spouse.
So stop worrying about such issues. The fears are completely unwarranted. All the doc is interested in is treating whatever medical problems you have. Your choice of underwear is not a medical problem.
