It was all a bit of fun until the question of circumcision was raised. That's when the convivial mood suddenly changed. Battle lines were quickly drawn with the men especially keen to jump in. With each side making impassioned protests that it is cleaner, safer or, conversely, barbaric and reduces sexual pleasure, I, happily uncircumcised, led the charge for my more natural brethren.

Whichever side of the scalpel you fall on, there's no denying that it is a hot-button issue across the board. But why?

"It is the combination of public health benefits, minor surgery, sex and vitriolic minorities opposed to it," explained Brian Morris, Professor of Molecular Medical Sciences at the University of Sydney and founder of website Circ Info.

Seeking expert medical opinion on the matter in order to gain a more impartial perspective, I was surprised to discover how divisive the issue is among doctors. I was warned by Morris that his opponents "use emotive fallacious propaganda to distort the truth and further their cause" and to be "extremely sceptical about everything they have to say."

Meanwhile, Dr Robert Darby, author of A Surgical Temptation: The Demonization of the Foreskin and the Rise of Circumcision in Britain, said, in response to claims that anti-circumcision practitioners are propagandists, "It is the circumcision advocates who are both ill-informed and tunnel-visioned."

"Considering that the Royal Australasian College of Physicians, the British Medical Association, the Canada Pediatric Society, the South African Medical Association, the Royal Dutch Medical Association, the American Academy of Pediatrics and medical authorities in Sweden, Norway, Denmark and Finland are all either against circumcision or do not recommend it, the evidence points clearly in the other direction," Darby noted.

Canvassing friends and family, mothers cited concerns of hygiene, acceptance by peers, and a desire for a boy to "look" like his father as deciding factors when it came to circumcising their children. As the practice is banned throughout Australian public hospitals, many parents opt for cosmetic circumcision performed by doctors in private clinics; these medical proponents add secondary illnesses and the prevention of sexually transmitted diseases to the list of circumcision's advantages.

"At least one in two uncircumcised males will experience a urinary tract infection, which in infancy leads to permanent kidney damage in half of cases," reported Morris. "Phimosis [tight foreskin], balanitis [inflammation] and high-risk HPV mean one in 1000 uncircumcised men will get penile cancer over their lifetime. The risk of prostate cancer has been found to be up to twice as common in uncircumcised men. In the female partners of uncircumcised men, risk of cervical cancer is up to five times higher, genital herpes two times higher and chlamydia up to five times higher."

But despite our comparatively high number of circumcised adults - a reported 54 per cent of Australian males between 16-64 - we suffer a higher incidence of sexually transmitted infections than, say, the Netherlands, where fewer than five per cent of adult males are circumcised. The USA, which has the highest proportion of circumcised adult men in the developed world, also has one of the highest rates of STIs, including HIV. In Australia there is no significant difference in the number of STIs between circumcised and uncircumcised men, except in relation to urethritis – which is more common among the circumcised. Furthermore, Dr Darby suggests that the role of circumcision in reducing HIV transmission – based on three African trials – is greatly exaggerated and doesn't translate to developed nations like Australia.

"The results of the African trials are not applicable to children and cannot be transposed to developed countries such as Australia, where the incidence of female-to-male transmission is extremely low," he said, adding that research linking uncircumcised men with cancer-causing HPV is inconclusive. "The idea that male infants or boys should be circumcised to reduce the risk of cervical cancer in hypothetical women some time in the future is grossly sexist: imagine if it were suggested that women ought to be circumcised to reduce the risk of cancer of the penis in men."

Then there's the argument of ethics. Putting aside the notion that your child will forget the trauma associated with tissue amputation, is the decision even yours to make?

With the possibility of potentially fatal complications like excessive blood loss and meningitis, and the far more common danger of excessive skin removal and accidental partial glans amputation, caregivers need to weigh up the proposed benefits against the risks of what is essentially cosmetic surgery. A growing trend towards foreskin restoration, of which a couple of my friends are a part, also indicates long-term psychological implications.

"For a surgical intervention to be ethical and indeed legal, the person must give informed consent," said Dr Darby. "This means that the doctors must provide an accurate account of all the possible complications and adverse outcomes of the operation. This rarely happens in the case of circumcision, where the warnings are often less comprehensive than those on a packet of aspirin ... The basic principles of bioethics have been set out by Beauchamp and Childress; circumcision of minors violates every one of them."

Though the practice is most prevalent in the Muslim population, many associate it more closely with Judaism. While it is a religious requirement for orthodox Jews, Ronald Goldman, PhD, author of Questioning Circumcision: A Jewish Perspective and head of the Jewish Circumcision Resource Center website, says that many secular Jews now opt for a welcoming ceremony over a brit milah, or bris, by changing the ritual to omit the circumcision.

"Many Jews are not aware that circumcision is a choice. It is psychologically easier to assume that there is no choice because it relieves the parents of dealing with the stress of making the decision and taking responsibility for it," he said. "This is changing as more information becomes available on the Internet and elsewhere. When Jews are aware of their choice, of course, they are more likely not to circumcise."

Then there's the factor that most adult men are concerned with: sexual pleasure. While professor Morris claims sexual pleasure "is either the same or better when circumcised", Darby acknowledges that while it's notoriously subjective, there's plenty of evidence that it reduces functionality of the penis. A recent Danish study discovered that circumcised men have a threefold risk of experiencing delayed orgasm and their female partners are twice as likely to be sexually frustrated.

"Not only does the foreskin contain the vast bulk of the pleasure-sensing nerves of the penis, but it provides a gliding action that facilitates and enhances sexual activity of all types," he said. "Before the 20th century it was well understood that the foreskin was the sexually dynamic and responsive component of the penis, which is why Victorian purity and anti-masturbation campaigners were so keen to cut it off."

So what became of my cousin's kid in the end? Well, citing our discussion over the Christmas table, as well as the fact that she was more concerned that he was born with fluid on his lungs and a congenital heart defect, her now healthy and adorable boy remains uncircumcised. A decision that Dr Darby would most certainly support.

"Leave the poor boy alone," he said of his advice to mums-to-be. "As an expectant mother and parent of a baby, you have far more important things to worry about than the shape of his dick."

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