Fifty years ago scientists were still working hard at cracking the human genetic code - now researchers are able to break down an individuals DNA in just a matter of hours. The advance not only allows doctors to find the cause of many illnesses and diseases but also to predict what patients could be susceptible to in the future. In Britain it is an area of medical testing that is becoming more and more popular as Suzanne Chislett explains from London.

Our genes make us who we are - Tall, short, brunettes or red-heads. They are the building blocks that decide our physical shape and also have a major impact on our health.

Advances in science now mean it is possible to break down DNA and examine its genetic sequence for possible defects, which could lead to illnesses and diseases such as diabetes, cardiovascular problems and muscular dystrophy.

"The technology for testing DNA has come on in leaps and bounds. It's much, much quicker and much, much easier now to read large amounts of DNA," says Doctor Fred Kavalier, a geneticist at Guy's Hospital in London.

Gathering information direct from our genes is not only useful to help doctors diagnose illnesses; it has also spawned a growing business in Britain.

People are increasingly turning to companies like Genetic Health here on London's famous Harley Street to get a personal breakdown of their genetic sequence and an assessment of what medical problems they could develop.

A simple swab test provides all the DNA needed for analysis.

"We'll provide them with a 50 page report that not only gives them the current clinical evidence that is out there at the moment but shows them what data we've drawn on to produce their risk but gives them an indication of how they can reduce their risk," says Brian Whitley, who is Managing Director of Genetic Health.

While some companies offer an impersonal service, sending out swab kits and then mailing clients back the analysis, others like to meet their potential clients.

"We put it in context with the whole other medical history of the individual but we won't leave the individual just hanging with their genetic data. They can come back and ask more questions, they're encouraged to go and do their own research and we can provide other support structures for them, such as exercise concepts, nutrition information - depending on where their level of interest is," Whitley said.

But there are wider concerns within Britain's scientific community that while the study of our genes is progressing apace - there are still too many unknowns to make any analysis as useful as it may appear.

As well as working at London's Guy's Hospital, Dr. Fred Kavalier is spokesperson for the British Society for Human Genetics. He says, "We don't know enough about all the genes that are involved in these diseases. We know about some of the genes but there are probably thousands of genes that are involved so it's really like looking at a couple of cards in a pack of cards and trying to say what the whole deck looks like."

Doctor Kavalier is concerned that people may take unnecessary risks with their health if told their risk of disease is low, or worry without cause if told they are in danger of developing a serious illness.

Current genetic profile tests cost between $1,000 and $2,000 U.S.

While some say that is a high fee to pay for information that, at the end of the day, can not change a person's medical fate, but others say knowing what could affect you later in life is priceless.