On an operating table in New Jersey, the patient keeps his eyes firmly fixed on the ceiling.Wearing a dressing gown, his fingers are interlaced across his chest and, from where I'm standing, he looks relaxed yet focused – as though he is about to divulge his troubles to a psychologist.But Tom, 35, who has asked to remain anonymous, is not here to talk about his emotional woes. He is having his penis enlarged. Urologist Dr Stuart Diamond steps forward and gently parts Tom's dressing gown, exposing the area he's about to work on. He leans in and plunges a half-inch needle into the side of his member, delivering a tiny dose of fat aimed at boosting its size.He does it again. And again. And again. It feels as though this goes on for a wince-inducing amount of time – in total, I count at least a dozen injections. Despite my own discomfort watching, Tom, I notice, doesn't flinch. I ask him if he's okay.'I can't feel a thing,' he answers, not breaking eye contact with the ceiling.After 10 to 15 minutes, the injections are over and the surgeon begins delicately massaging and manipulating Tom's manhood to ensure the fat is evenly distributed.Then, about 45 minutes after the procedure began, it's over. Tom's member is dabbed clean of the tiny spots of blood oozing from the puncture sites, and he stands up, finally daring to look down. Dr Stuart Diamond and his wife Noelle are pictured above. Dr DIamond is administering the aloeClae injections to Tom's penis The above picture shows the alloClae fat injections being prepared Dr Diamond is shown above holding the filler injection. He is in a side room away from the main room where the injections into the penis are carried out 'I'm thrilled!' he declares. 'It looks great!'Tom is one of a reportedly increasing number of men in the US opting for cosmetic procedures to increase the size of their penis.Such treatments have been around for decades. One of the most common techniques involves using dermal filler – a gel, usually made from hyaluronic acid, the same substance widely used to plump lips and smooth wrinkles.Injected beneath the skin of the penis, the gel adds volume, increasing its girth rather than making it significantly longer.But what Tom has just had injected is very different.He is one of just three men in the country to have undergone an experimental new procedure using donor fat – tissue harvested from the bodies of deceased people – to enlarge the penis.I was the first journalist invited to watch the technique being performed.The treatment uses a product called alloClae, which takes donated fat, extensively processes and purifies it, then packages it as an off-the-shelf product that can be shipped to cosmetic clinics and injected beneath the skin to add volume. It may sound macabre, but donated human tissue has long been used in medicine. Bone, skin and tendons, for instance, are routinely transplanted or used in reconstructive procedures.Now the same principle is making its way into cosmetic medicine. Fat is attractive as a filler because it can provide soft, natural-feeling volume and, unlike conventional fillers, can become incorporated into the body's own tissue.Traditionally, however, using fat for cosmetic enhancement has meant undergoing liposuction to harvest it from another part of your own body. AlloClae is designed to get around that problem: it provides processed donor fat ready to inject, without the patient needing a second procedure to supply it.The penis-enlarging procedure costs between $8,000 and $12,000.There is no medical need for it – it is entirely cosmetic, designed to increase girth rather than improve sexual function. Yet doctors say demand for cosmetic penis enlargement has grown in recent years, no doubt fueled by an insecurity that is remarkably common.Surveys suggest about half of men worry about their penis size, although doctors say virtually all have no medical reason to do so. Tom is one of just three men in the country to have undergone an experimental new procedure using donor fat – tissue harvested from the bodies of deceased people – to enlarge the penis Dr Diamond is shown above injecting filler into Tom's penis during the procedure. His wife Noelle is shown preparing the filler for injections in the backgroundWhile dermal fillers are FDA-approved for adding volume to areas including the lips, cheeks and chin, they are not approved for injection into the penis. And there are significant potential complications including injury, scarring, infection and angled erections. With injectable fillers, there is also a risk that the material can migrate or collect unevenly, leaving the penis looking lumpy or misshapen.For Tom, however, the potential risks were worth taking. His penis functioned normally and no partner had ever commented negatively on its size, he said, but it had worried him for virtually his entire life.He simply no longer wanted to feel insecure or anxious about it, he told me. Before the procedure, his penis measured four inches when stretched while flaccid. Doctors use this measurement, rather than erect length, because it provides a more consistent way of assessing penis size in the clinic and is the standard method used to diagnose conditions such as micropenis.Tom's measurement was below the average stretched length of 5.2 inches but remained just above the threshold for a micropenis – the medical term for an abnormally small but otherwise normally formed penis. This is generally defined in an adult as a stretched flaccid length of less than 3.7 inches. After the injections, Tom's stretched flaccid length had increased by half an inch, to 4.5 inches.But the far more significant change was in girth – the circumference of the penis, and the principal target of injectable enlargement procedures.Afterward, this increased from 3.5 inches, which is around average, to 5 inches.For Tom, he said he first became worried about the size of his penis in his teenage years. 'It was in the baseball changing rooms when I first looked and thought, hey, mine's shorter than everyone else's,' he says. 'No one ever commented, but it made me feel weird to take my pants off. Normally, I would rush to put them back on quickly. 'When I joined the military, no one said anything again, but still, in the changing rooms, I saw mine was not as big as the others.'Tom has been married to his childhood sweetheart for 16 years, who has also never said anything about his penis size, and the pair have three children together, now aged 14, 12 and six years old.Deciding their family was complete, a few years ago he chose to undergo a vasectomy. But penis size remained a concern.