Medfet is interesting to me, even if I don't relate to most of the fetishes therein. I think in general, it's at worst a harmless thing. Honestly, I think it's harmful when people don't know their true sexual selves. A community like this can really help a person accept themselves.
All that said, my particular medfet has some moral challenges to it. At least I think so. YMMV. My medfet basically requires a girl to be sick in such a way that she needs to wear a mask in certain public situations. Think organ transplants, multiple chemical sensitivity, peanut allergy and the like. My favorite such masks that I've seen a patient wear are 3M 1860 (those thick, double-banded aqua N95 disposables. If any of you is a nurse by profession, you likely know them) and cartridge respirators (yes, one hospital in northern CA has patients wear them immediately after transplant for a phase).
About 11 years ago, I met a 19 year old girl (I was 30) who was going for a lung transplant. She had an account on deviantART where she showed off her artwork, which included modeling. Some of her modeling had her wearing a cartridge respirator. In her bio, she mentions the disease she lives with (CF), and elsewhere in it, she states being open for commissions.
I get all nervous, but I go ahead and PM her, saying that I know what CF is and that I actually have a fetish for girls in masks (I am not yet aware of the term "medfet"). I propose a photoshoot and give her my AIM. Within an hour, she appears on my AIM and says "hi". I'm terrified at this point, but she puts me at ease and we work something out. We became true friends for over a year, during which time I got to see her several times (she lived in my state), including in each of two of the masks she had in her wardrobe.
Over that time, I befriend several of her friends, albeit online, and at least two of them mention my fetish in a favorable way (my friend had told them. I didn't.).
I'm rambling. Since that time, it's been mixed. I've now learned to keep it to myself. I look at pics of such medfet situations. Maybe a girl is out on her hospital floor in whatever mask they make you wear there. Another girl's doctor ordered her to wear a 3M cartridge respirator on a plane. Etc. etc. But I never comment "cute pic" or something if she's in a mask for medical reasons.
I'm mixed, I guess. I love that this is a fetish umbrealla, but I get lonely at how secretive I need to be. I'm physically disabled, and so that severely limits any opportunities for romance. It';s just been kind of a taboo. Plus, I've moved around a whole lot. So, my social chops are a bit lacking.
I do love my fantasy world overall. I can dream of whatever girl I like, real or imagined, and she is wearing a mask with her normal clothes: schoolgirl-type outfits, pajamas, even a bikini at times. And it's not looked down upon. Like Japan, I guess, but in english and with WASPY athletic soccer, ballet and gymnastic girls.