It's good to have rules in life. Why then do we get no such guidance when it comes to hand-to-gland combat? Sure, there's the old adage "masturbation sends you blind" but when I once asked my dad about this he simply advised "stop when you have to wear glasses". I have contact lenses. Jokes aside, there's little doubt the ubiquity of internet pornography has, for many men and boys, transformed "roughing the suspect" from a distracting past-time to a pathological behaviour. A first of its kind study released last week by researchers at the University of Sydney revealed the destructive effect excessive porn viewing can have on users and their families. Interestingly, in all the news coverage about the study, I didn't see the "m" word used once - and let's face it - it's the masturbating to porn that causes problems.

Eighty-five per cent of the 800 porn users surveyed were male, and more than half married or in de facto relationships. Forty-seven per cent spent between 30 minutes and three hours a day watching porn. That's not good. Internationally, Professor Stuart Brody, of the University of the West of Scotland, has also published numerous studies on the subject and told me last week "any masturbation is associated with poorer health outcomes and less life satisfaction". Studies in 1976, 2002 and 2004 also show greater masturbation frequency was associated with more depressive symptoms; a 2007 study showed that it results in less happiness; and 2010 and 2011 studies correlate it with "anxious attachment, immature psychological defence mechanisms, greater blood pressure reactivity to stress, and dissatisfaction with one's life in general". The old chestnut that masturbation staves off prostate cancer may also have been disproved as well - in fact, it seems it's only ejaculation via penile-vaginal intercourse (PVI) that correlates positively, while wanking "frequency is more often related to an increased risk" of prostate cancer, according to Brody's 2010 study.

"It is interesting to note that masturbation is also associated with other problems of the prostate (higher prostate specific antigen levels and swollen or tender prostate) and, compared with the ejaculate obtained from PVI, the ejaculate obtained from masturbation has markers of poorer prostatic function and lesser elimination of waste products," writes one of Brody's colleagues, Rui Miguel Costa, in a letter published online last month in the peer-reviewed journal Archives of Sexual Behavior. Costa says "the only sexual behaviour consistently related to better psychological and physical health is PVI". He told me last week via email he'd recommend "no masturbation at all, as I would say no junk food at all, but I believe it would be unrealistic to many people". He conceded "it's possible some of the bad things associated with masturbation result from subtle to not-so-subtle difficulties in relations with the opposite sex". Other health professionals are more sceptical, saying we should not confuse the symptom with the cause: "It's like saying playing World of Warcraft makes you a confused virgin. Of course it doesn't, it's more that shy, introverted and socially awkward people are more likely to develop interests which are solitary," said one local physiologist I spoke to. "To make an association like this work in a group of people, all you need is a sub-population of people who are (a) very lonely and (b) wanking themselves rigid to create an association in the population as a whole," he said.

"It might not mean that the same is true at the other end, that people who have a lot of normative sex but don't masturbate, are healthier and/or better. "Think on this - masturbation, by definition, is a marker of loneliness. Excessive masturbation may well be a sign of the inability to relate to people or form normal human relationships, but that is a symptom, not a cause. Turning it into a health association (masturbation does x) is not the same as "masturbation occurs in the presence of x," he said. However, if we're to believe the Sydney University study, there are also many men in relationships who masturbate, and do it to excess. They're the ones who might need to recognise that sex, no matter how routine, is a truly a case of reality being much better - and better for you - than fantasy. SYDNEY WRITER'S FESTIVAL

I'll be talking with Alex Mitchell, author of Come The Revolution: A memoir and Kevin Rudd's former head of spin, Lachlan Harris, this Friday, May 18, 2012, at the Philharmonia Studio, Pier 4/5, Hickson Road, Walsh Bay from 1pm to 2pm. It's free. For more info, go here. Sam de Brito's latest novel Hello Darkness is in bookstores now. You can follow him on Twitter here. His email address is here.