"It also could be argued that it's a combination of genes, and a combination of an accident," Roslin said.
He said most people would consider a car crash an accident but a culture that supports obesity is not.
"If I eat too much when there's available food [and need surgery]," then he guessed people would argue it would not be an accident. But if someone drank too much and "I got myself drunk and drove into a tree, then I'm entitled to a nose job?" he asked.
Roslin said the flaps of excess skin left after losing hundreds of pounds can sometimes cause rashes. He wondered if the patients who had rashes would be exempt from the tax because it treated a medical problem, but the patients who didn't have a rash would have to pay.
A host of other surgeries to correct physical disfigurements that are not congenital, or that were a side effects of other medical treatments, might not fall under the exceptions listed in the bill, either.
Several doctors wondered whether breast reconstruction after a mastectomy would count as cosmetic because a "disfiguring disease" didn't misshape a woman's breasts, the treatment did.
In a similar case, liposuction would likely be taxed in many cases but liposuction for lipodystrophy might be open to debate. Lipodystrophy is a misplaced collection of fat, often seen as a hump on the back of the neck, that is caused by certain medications -- including protease inhibitors for HIV -- but not caused by accidents or disfiguring diseases.
"Would a condition that is not physically a medical issue, but is causing emotional distress to a patient, be subject to a 5 percent tax?" asked Dr. Mark Abdelmalek, chief of laser and dermatologic surgery at Drexel University College of Medicine in Philadelphia.
Abdelmalek could rattle off a list of non-congenital abnormalities that are medical problems but could be taxed as cosmetic issues under the language of the bill, including treating alopecia (hair loss) in women, and removal or destruction of irritated skin tags.
Dr. Garry S. Brody, professor emeritus of the University of Southern California Keck School of Medicine, wondered if the broad language regarding "payment for a procedure" would cause confusion and a host of loopholes.
"[There is] no indication as to whether this includes ancillary fees such as anesthesia and facility fees as well, as the physicians fees," Brody said. "It will be an accounting nightmare and probably tempt fraudulent billing.
"As this is a private relationship with doctor and patient, it will probably be under-reported."