19/02/2016 10:47 AM AEDT | Updated 15/07/2016 12:51 PM AEST

Sometimes Asking Questions Provides You With Answers That May Be Uncomfortable

People have been aware of a purported link between mobile phones and brain cancer for some time now. The easy argument is that mobile phones have been around since 1988 and there's been no tidal wave of tumours, so 'case closed'. But not enough people had mobile phones in 1988 to make any assessment on population risk.

Visuals Unlimited, Inc./Scientifica via Getty Images
Thermogram of a male teenager talking on a cell phone. The temperature scale runs from white (warmest) through red, yellow, green and cyan, blue and black (coldest).

The claims that our program "should never have aired" should not sit well with the public. At best, it's an over-reaction. At worst, it's a form of censorship.

Sometimes in science asking questions provides you with answers that may be unsettling. Not because they are conclusive, but because they are inconclusive. It's the duty of scientists and science reporters to encourage critical thinking on issues that are still up for debate.

Several other counties around the world have more stringent radio frequency safety thresholds than Australia. Italy, China, Switzerland and Russia have wireless safety limits, which are a hundred times more stringent than our own. In France, they restrict advertising of mobile phones to children. They have also banned Wi-Fi in nurseries and day care centres.

So I decided to investigate. Why are some countries making these changes and not Australia? To say that this is a fringe view is not sustainable.

Wireless technology is relatively new and the science in this area is not as settled as is often claimed. Especially in relation to children. That is why a study is currently underway, involving over 14 countries, which is assessing whether the use of mobile phones at an early age increases the rates of early onset brain tumours in 1000 young people. The results will be released this year.

To be clear, we never stated that Wi-Fi definitively causes cancer, as has been incorrectly asserted. While there are associations or links between heavy mobile phone use and glioma (malignant brain tumours), we did not suggest direct causation.

People have been aware of a purported link between mobile phones and brain cancer for some time now. The easy argument is that mobile phones have been around since 1988 and there's been no tidal wave of tumours, so 'case closed'. But not enough people had mobile phones in 1988 to make any assessment on population risk. The explosion of wireless technology, smartphones and Wi-Fi has only occurred in the past 10 years. Given that brain cancers are rare, it's unlikely there would be sufficient numbers to detect an increase in their incidence in the general population (trend data).

But if you look at specific groups with brain tumours, and compare them to people who don't have brain tumours, studies show 4-8 times more glioma detected in people who began to use a cell phone before 20 years of age.

We cited the Bioinitiative Report, which outlines hundreds of peer-reviewed papers by independent scientists, detailing studies on how cell biology can be disrupted by exposure to radiation from wireless devices. Even though ARPANSA, our safety agency, says there's no established scientific evidence that the use of mobile phones or Wi-Fi devices cause any health effects, we cited the major case-controlled studies (Interphone, Hardell and CERENAT), which demonstrate a link between heavy mobile phone use and glioma (malignant brain tumours).

Are these studies perfect? No, but they are the best we currently have and they have been replicated three times, which is important from a scientific perspective.

This is not a completely polarised debate among scientists. There is consensus that parents should limit their children's use of mobile phones, a statement made by ARPANSA in the program.

As an investigative journalist, I am used to taking some heat from critics. It's part of the job. Catalyst is no stranger to controversy. As investigators, we have studied emerging scientific debates at home and abroad, and brought them into Australian living rooms. What was perceived as controversial a few years ago, like discussions on dietary sugar or the over-prescription of cholesterol-lowering medications called statins, is now widely debated overseas by mainstream media outlets.

We always knew Dr Davis was a dissenting voice in this debate. But that's never a reason not to interview someone, especially as she is extremely well credentialed.

We also invited two high profile critics of Davis onto the program to dispute her claims: Professor Simon Chapman and Professor Bernard Stewart, but they both declined. Perplexingly, they have since launched a passionate rebuttal of Davis in print media, something they could have done within the program itself.

It's surprising that Dr Davis provoked such a visceral response online. Dr Davis has previously appeared on most other networks and papers in Australia without attracting the same hysteria that occurred on Twitter. But science isn't settled in 140 characters. And Twitter is renowned for being more of a lynch mob than a considered jury. The online backlash was irrelevant to the more important scientific debate.

Catalyst was accused of scaremongering. It's an overused term. It's routinely used in politics to dismiss opposition policies. Reporting on terrorist threats, the Zika virus and crime sprees could also be argued to cause anxiety among the general population. But it's a price we're all willing to pay for free and diverse speech.

As one viewer wrote, "Shutting down discussion and the flow of information on the basis it might frighten people is 'nanny state-ism' and censorship gone mad and could potentially perpetuate more of the cigarette and drug disasters of the past".

So were we 'scaremongering'? Well, Davis herself stated that no-one should stop using their wireless devices but be more measured in how they're used. She stressed that "distance is your friend" a concept that is echoed in the RF warnings within the phones themselves. She also suggested people reconsider whether they should have their router in the bedroom. This is hardly sensationalist stuff.

The great thing about science is that new discoveries are constantly made and orthodoxies change. Sometimes so-called "fringe" views move into the mainstream, forcing governments to change policies to prevent public harm. This has happened many times. Think back to thalidomide, asbestos, tobacco. We are not suggesting this will necessarily happen in the case of wireless technology, but it's also not scientific to claim the door has been slammed shut on this discussion.

Both side of the debate received airtime and the conclusion of the program showed that in the face of uncertainty, people might want to be more cautious about how they use the technology.

After all that has happened, my concern is that the ability to have this conversation might be curtailed.