This might be a dumb answer, but I’ll give it a shot. I have a scar on my chin. People see it and ask me how I got it. I then grudgingly explain that my little brother threw something sharp at me when I was 16. I used to have stretch marks on my arms. People would see it and instantly ask, and I would have to grudgingly tell them that I had been overdoing it with weights (not a good idea to start at age 13). I just got over a bout with bronchitis, and everyone kept asking me how I got it. I grudgingly tell them that I have no idea, other than an anonymous bacterium managed to sneak into my system. I imagine to an extreme degree this is what is happening with your dilemma – although I agree it’s tasteless to inquire of such a thing, as it is a sensitive matter.