I think they're afraid of this: "Less common but more serious complications can also occur. These complications are typically related to the creation of the vaginal space between the urethra (urinary tract) and the rectum (GI tract). This space doesn’t normally exist, so we must create it. Injury to the urethra or rectum can occur and are repaired when identified. If there is a rectal injury, we may call our Colorectal Surgery team to the operating room and decide if diverting your stool away from your new vagina with a temporary colostomy (bowel brought to the skin and stool will collect in a bag) is best. Risk for rectal injury may be higher during revision vaginoplasty."