When I knocked on Mitch Hunter's door in the suburbs of Indianapolis, I really didn't know what to expect.
I had seen photos of him as a young soldier and photos of him after 10 years of plastic surgery, but now I was about to meet him - four months after he had received one of the world's first full face transplants.
He opened the door with his 18-month-old son, Clayton, in his arms and I was stunned.
Mitch is not the handsome young man he once was, but the transformation from the face he had just six months ago is astonishing. Looking from Mitch to his young son, I could even see the family resemblance.
Mitch was 20 years old when a car he was a passenger in crashed into a pole containing a 10,000 volt electrical cable.
He tried to rescue a fellow passenger, but while doing so got the full blast from the electrical cable through his leg and face. He lost the leg and most of his face was burnt off. Over the next 10 years, surgeons tried to rebuild his face, but the results were patchy.
It was the birth of his son Clayton that made Mitch finally decide to have a full face transplant, only the third ever performed in the United States.
"I've had kids hide and run behind their moms because they were so scared when they saw me," he explained."That was hard to cope with because my friends started having kids, then my brother had a kid. Then I had Clayton and I didn't want kids to be afraid of me any more."
Mitch's operation was funded by an unusual collaboration between the Brigham and Women's hospital in Boston and the US military.
There are so many soldiers coming back home from the conflicts in Afghanistan with severely mutilated faces and bodies that the military has decided to fund research into novel ways of repairing them. This includes paying for hand and face transplants.
Dr Bohdan Pomahac, who works at the Brigham and Women's hospital, has now done three full face transplants and, with military funding, is preparing to do another five. Mitch, who he operated on in April 2011, was his second patient.
To qualify for the surgery the patient must be missing at least 25% of their face. Dr Pomahac thinks there must be at least 200-300 veterans who would be eligible and he is hoping some will put their names forward.Continue reading the main story A major problem with face and hand transplants is patients have to take drugs to suppress their immune system or the body will reject the organ. This makes patients more vulnerable to infection and can precipitate conditions like diabetes. A new technique aims to re-educate the body's immune system to accept the transplanted organ by an infusion of bone marrow from the donor.Known as the Pittsburgh Protocol, it was developed at the University of Pittsburgh. London's Royal Free Hospital is keen to adopt the technique, with director of surgery and trauma Professor Peter Butler hoping to establish UK expertise in arm and face transplants.Finding a donor is, surprisingly enough, not that difficult. Dr Pomahac said he would prefer the donor to be young and of the same sex, though computer reconstructions suggest that a female face transplanted onto a male would look all right, although it has not yet been tried.
The full thickness of the face is transplanted, but what really determines how a patient will look afterwards is the underlying bone structure of their faces.
The operation itself went smoothly. A team of surgeons removed Mitch's old face before the new face was carried into the operating theatre by Dr Pomahac.
They joined up arteries from Mitch's body to the new face, and also connected three nerves. Finally the new face, with nose, lips and muscle, was stitched into place. The whole operation took 14 hours, somewhat less than his first.
"We have planned on simplifying it, making it more reproducible and easier for people to do and I think we have accomplished that goal," said Dr Pomahac. "But with every operation we learn an enormous amount."
Initially there was a lot of swelling. "It looked like the face of a 200lb (90kg) guy, it was that swollen," Mitch told me, but as the swelling went down, his old features started to come through.Mitch's brother Mark, who is older by a year, says he could see the old Mitch from day one.
"I didn't know how I was going to react, but when I walked through the door of the hospital it was him, my brother."
Katerina, Mitch's partner, is an old school friend, and they got together several years ago, long before the transplant.
She said she quickly got used to the fact that he had a damaged face and accepted him for who he was, though she realised Mitch was unhappy and avoided going out.
Her reaction to the transplant? "I think it's just crazy - the fact that medical science has come this far, what they are able to do. It's just amazing."
When I asked her if it was strange kissing the lips of a dead man, she replied: "I had never kissed him with lips before."
Mitch says sensation is returning and he can now do things like raise his eyebrows, purse his lips and smile. He expects these improvements to continue.
"There is still a little extra skin in places," he said, "but I'm told that when everything is said and done and finalised, I will look a lot like I used to."
Dr Pomahac agrees that things should steadily improve, particularly sensation. "The first sensation develops within a month or two. It's very crude. But it continues to improve and in about 18 months I would expect that Mitch is going to be feeling near normal."Michael Mosley presents the second episode of Frontline Medicine on BBC Two at 21:00 on Sunday 27 November 2011. Watch via iPlayer (UK only) and catch up on episode one at the above link.