Worries about the Pill go back almost to when it was first introduced more than 30 years ago, but its use has almost certainly saved more lives than it has destroyed. The more recent scare, following a Government health warning in 1995, led to a dramatic surge in abortions. Within the nine- month period after the alert was issued, some 10,000 pregnancies were terminated, the highest abortion rate since records began in 1969.
Now we know the lifetime risk of taking the Pill is actually less than the risk of having an abortion and of giving birth. The evidence of the longest study into taking the oral contraceptive - extending over 25 years - shows that women who are on it are at no greater risk of dying from heart disease or cancers than women who have never used it. Some doctors believe that the Pill may actually protect women against certain cancers.
Mobile phones, a far more recent innovation, seem to be following a similar fate of scare and counter-scare. No sooner had millions of people decided to use them, when the first doubts about their potential health risks emerged. A gaggle of scientists were cited as having found evidence, if not hard proof, that mobiles could cause headaches, memory loss and even brain tumours. Yet the only study so far published on the effects of mobiles on the brain has found no amnesia, just a slight improvement in a person's reaction time.
If we look more carefully at the mobile phone controversy, we see it has all the necessary ingredients to make the perfect scare story. First, the devices in question are ubiquitous and so any scare can be seen to affect all of us and not just an insignificant minority. Then there is the mystery of what the mobile phones emit - microwave radiation. It not only sounds sinister, it is invisible, and anything we can't see, can't be trusted. The final ingredient is the mysterious nature of the ill-effects themselves. The precise cause of a cancer is always a mystery and it is a natural reaction to want to blame a tumour on something, even if the disease was in fact an inevitable outcome for the person in question. And who can say whether a sudden moment of forgetfulness was caused by phone radiation, or the attention-diverting nature of the conversation itself?
This is where science is supposed to help out. The researchers at Bristol University conducted a series of tests designed to see if mobile phones could cause loss of short-term memory, or indeed any other affects on mental ability. Although they found that the volunteers in the experiment suffered no apparent memory loss, the microwave radiation emitted from the devices did seem to shorten the time it took them to perform simple mental tasks.
One possible explanation is that the microwaves of a mobile phone, although far less powerful than those used in a microwave oven, slightly warmed the brain, and possibly increased the flow of blood to the nerve junctions between one part of the brain and another. It would be easy for a layperson to conclude that scientists had after all found that mobile phones can cook your brains.
The reality, however, is quite different. Although the scientists had recorded a definite observation - an improved reaction time - their attempt at an explanation was just that, an attempt. In fact it was noticeable that Alan Preece, the medical physicist in charge of the research, felt that he was not qualified to speculate on what the results of the experiment meant in terms of risk to health. That was up to expert neurologists, he said.
Dr Preece was doing what any self-respecting scientist would do when faced with a difficult problem. He presents his results for criticism by his peers, gets them published in a reputable scientific journal and then waits for other experts to either repeat the experiment or to reinterpret the results another way. It can be a slow and protracted business, but it's how science is done.
The media, however, works on much shorter timescales with an inherent desire to clutter their stories with fewer caveats than do scientific papers. Some scientists consequently blame newspapers for creating scares, and possibly with some justification in Dr Preece's case, given that at least one national newspaper prematurely claimed that his research had shown that mobiles cause memory loss - precisely the opposite of what he had actually found.
However, it would be unjust to blame the messenger for all scares. Take for instance the outburst two years ago over the safe level of red meat in the diet. In 1997, Frank Dobson, the Health Secretary, issued a recommendation that people should eat less red meat because of the increased risk of cancer. He said that people eating average amounts of meat - 90g a day or between eight and 10 average-sized portions a week - should reduce their consumption. Naturally, given that the advice came from a senior minister of Her Majesty's Government, the public became confused and scared.
However, the committee of experts who were advising Mr Dobson at the time appeared to have been split on the issue. In fact, by the time they published their recommendations six months later, the Committee on Medical Aspects of Food and Nutrition (Coma) had omitted Mr Dobson's specific recommendation, saying instead that people who ate considerably more than average amounts of red meat (more than 140g a day) "might benefit from, and should consider, a reduction in intake". Significantly weaker advice than the Government had previously issued.
The point is that even experts can confuse those they are supposed to be advising. They can and do frequently disagree over what constitutes a genuine risk to the public. This confusion can be misinterpreted as the advice goes from one committee to another and finally emerges as the official position.
The saga over "mad cow" disease has told us how difficult it is for scientists to estimate risks for what amounts to virtually unknowable outcomes. For scientists to say "we don't actually know" is quite easy, but it is virtually impossible for a politician to admit ignorance when he or she is responsible for public health and safety. This is why public anxiety peaked when the former Tory government's line of "no conceivable risk" of eating beef, proved to be so disastrously wrong, when the link was confirmed between BSE and the human version of the brain disease.
It is now a rather lamentable fact that the public are more wary of scientists and government officials than they are of the claims made by pressure groups such as Friends of the Earth and Greenpeace, who are working to an agenda. In the propaganda war over genetically modified foods, for instance, the environmentalists are clearly winning. Yet scientifically there is a strong case for saying that GM technology could provide genuine benefits for humankind. A type of GM rice that is rich in iron, for instance, could be grown commercially in south-east Asia to help thousands of children suffering long-term harm from iron-deficiency in their diet. In Britain, however, the public is too risk-aware, especially over food, to accept GM technology with open arms.
There is, of course, no such thing as a risk-free life. So many things can happen between getting out of bed in the morning and turning off the light at night. I could, if I was that way inclined, make out a reasonable case for banning that little-known lethal weapon, the toothbrush. Every year about 40 children have to be admitted to hospital for fairly serious surgical treatment after injuring themselves while brushing their teeth. Of course the health benefits of clean teeth far outweigh the potential hazards. For now, at least, the toothbrush is safe.Reuse content