A company has launched an online service that will enable people to receive a profile of their own genome.
Customers will be able to access their genome online
DeCode Genetics says subscribers will be able to assess the likelihood of developing certain diseases.
Customers will be able to see if they are at risk from illnesses such as heart disease and certain cancers, a spokesman for the Icelandic firm said.
Critics condemned the service, saying people could misinterpret the data and become unnecessarily concerned.
"People who buy the service will have the opportunity to look at their genome and compare it to the genomes of those who in the past have been shown to be at particular risk of certain diseases," said Kari Stefansson, chief executive of DeCode Genetics.
"It will also give people an opportunity to put their genome in context of what we know about the genetics of population history," he added.
"So people will be able to figure out where their ancestors came from."
Customers receive an analysis of their genome a few weeks after sending a cheek swab to the company.
Dr Stefansson said it was the first time that such a service had been available to the public.
Critics have voiced concern, fearing that it would overemphasise the role of genes in common diseases.
"Bad diet, smoking, poverty and pollution are all factors that are probably much more important," GeneWatch UK director Helen Wallace told BBC News.
"So there is a real danger that people taking these tests will be misled about their health."
"We are not so concerned about people having information," explained Dr Wallace. "We are concerned about them having misinformation."
But Dr Stefansson said the company felt it had a duty to make the service available to people who wanted to use it.
"DeCode Genetics has been a leading force in the study of genetics of common diseases over the past 10 years," he said.
"We have participated in communicating those results through scientific papers and the (media).
"So we feel that we have a certain obligation to help the public to put it into context."