Guess how many mobile phones there are in Australia five million? Ten million? The answer is a staggering 19 million that's nearly one for each person.
But are we creating a headache for ourselves … or worse? Basically, are mobile phones bad for our health?
The air is full of their signals. But is it safe?
You probably can't remember not having one, but mobile phones have only been with us for 25 years. It's not long, particularly in terms of studying their effects on our bodies.
So we're taking a look at some of the health questions surrounding mobiles: cancer, headaches and kids' safety.
You'd think Andrew Gideon would be a sitting duck as a mobile phone health target. He's on the thing day in, day out.
Andrew runs an online menswear accessory store. His whole day is spent wheeling and dealing with clients, suppliers and banks.
"I spend probably three-and-a-half to four hours a day on my mobile phone. Over a week that could be 15 hours or so," he says.
Here's what he's exposing himself to: every time we use our mobile phones, we get an earful of what's called "radio frequency", or "microwave" radiation. Some of the radiation is absorbed by our body tissue. The radiation is enough to make tissue molecules vibrate and increase in temperature by a fraction of a degree. But it's so small we're not even aware of it.
Guys like Alasdair Philips are aware of it, and it worries them. He's director of Power Watch, a British consumer protection group.
Alisdair's built a little gadget to demonstrate just how much electromagnetic radiation is out there.
"So if I turn it on here at the moment there's just a hissing noise that it produces. If I put a little FM walkie-talkie on you can hear it but it's basically just a gentle change in the hiss level … If I now put this digital cordless phone on … that's filling the room with this [a loud hiss noise]... which goes on 24/7 even when you're not using the phone."
Alasdair is worried enough to screen his house from electromagnetic radiation.
Way back, when we dialled phones and phone signals only ran along copper wires, radio frequency transmissions were tiny. Then, in 1981, phones went mobile from brick-sized to pocket-sized to pint-sized. The only thing that hasn't got smaller is our exposure to radio frequencies.
"The levels of those are now billions of times greater than we had only seventy years ago. It's completely dominating the electromagnetic field on earth," says Alasdair.
So that's what Andrew, and the rest of us, are exposing ourselves to … so is it dangerous?
Andrew gives himself a clean bill of health: "I haven't noticed any side effects from using a mobile phone. No headaches, no dizziness, nothing of that calibre."
The closest Andrew gets to a health problem is heartburn when his monthly mobile bill comes in!
But for some people, the mobile poses a far more serious problem. If you're worried about the health effects of your mobile phone, you'll get no argument from Brian Stein. He's CEO of a billion-dollar chilled food company in the UK.
Brian was a heavy mobile phone user for 14 years. Then, he developed "electromagnetic hypersensitivity".
"When I picked the phone up and put it to my head, the pain was instantaneous and it was if something in my ear had burst. The pain was that severe," he says.
Brian became so sensitive to electrical emissions he banished computers, fluorescent lights and computer-controlled heating from his office.
To use the telephone Brian resorts to a low-tech speakerphone.
"Can't watch TV, can't use a computer, can't go to the cinema, can't listen to music…" says Brian.
To demonstrate he's not imagining his symptoms, Brian had himself tested by a university. He was exposed to a mobile phone base station mast for almost an hour.
"And I bled internally for a fortnight and that's what happens to me if I have too much exposure to a mast."
Brian's case is extreme, and the cause of his hypersensitivity remains contentious. But for you and I, and the 19 million other mobile users in Australia, there's one single health question we all want an answer to can they give us cancer?
"At the moment there's very little information or evidence to support the idea that radio frequency radiation will disrupt cells in any way. That might cause them to go on and become cancerous cells," says Professor Patricia McKinney who authored a huge 'Interphone' study.
It looked at 6000 cancer cases, in fourteen countries including Australia to see if mobile phones caused serious problems, like brain tumours.
"What we can say is there doesn't appear to be an increased risk of developing a brain tumour from using a mobile phone. However, that's not to say in any one individual case that we can completely rule that circumstance out," she says.
That's not entirely reassuring, and the fact is, we can't be any surer than that. Many tumours take decades to develop and we haven't been mobile phone maniacs for that long. And, let's face it, the things are so darn useful, lots of folks would risk it, regardless.
We'll risk it for ourselves, but what about our kids? Are their thinner skulls and developing brains at greater risk from radiation?
Max is 13 and his dad Carl wants to do the right thing and keep in touch during the day.
"The kids are old enough now to go out and play in the park by themselves. But if they need someone to come and get them or save them, or might want to know where they are, it's convenient to have them available on the phone," says Carl.
With the best intentions in the world should we still be more cautious where kids are concerned?
"The idea is that children's brains are still developing, and that these tissues may be particularly vulnerable in children, and therefore just to err on the side of caution," says Professor McKinney.
The good news is the World Health Organisation says there's no evidence that children are more at risk. But parents might like to limit their kids' exposure by keeping calls short.
Right now, there's a bit of a confusing whirlwind of information about mobiles. Scientists say there's no plausible reason why they should cause cancer. Well-meaning consumer advocates say it's too early to tell. If you're worried, there are some simple ways to limit your exposure.
Remember our mate Andrew? Fifteen hours on the mobile a week, but he's trying to play safe. A hands-free earpiece keeps the phone away from his head, it can reduce exposure by 94 percent.
Another way to reduce exposure? Choose a phone with a low specific absorption rate, or SAR value. SAR shows how much radiation is absorbed by body tissue when your phone's at maximum power. The Australian SAR limit is two watts per kilogram of tissue, but some handsets go as low as 0.2.
But the commonsense way to reduce exposure to mobile phone radiation is for everyone to keep call times short!
The good news is at this point in the communications revolution there is no convincing evidence that mobile phones will make you sick. But it always pays to be cautious!
"I think the long-term effect of mobile phone use and whether it causes cancer, or depression, or sleeplessness, or a whole range of illnesses is really not possible to say. I think we have to wait. We have to study further. We have to investigate long-term use and then we'll be able to answer that question," says Professor McKinney.
Meanwhile, we'll all keep using our mobile phones hoping that, like all good things in life, moderation wins the day.
- If you're on the phone while driving, use hands-free. Studies have found talking on a hand-held phone impairs your driving ability to the same degree as having a blood alcohol level of 0.08. But even hands-free, your phone is a distraction … so use it sparingly.