A personal DNA testing kit that gives users an insight into their genetic make-up has gone on sale in the UK.
The 23andMe Personal Genome Service (PGS) costs £125 and claims to offer access to more than 100 pieces of information about a person's health, ancestry and family traits.
Users spit in a tube, seal it and send it off to be analysed in a laboratory.
After four to six weeks they receive an email notifying them that the results are ready and log in online to see a detailed report.
23andMe, which has been part-funded by Google, said the tool is not "diagnostic" but includes results of tests for genes associated with inherited conditions such as cystic fibrosis or sickle cell anaemia.
It also tests for genes that may reveal risk factors for diseases or conditions such as blood clotting, Alzheimer's or Parkinson's.
In addition to findings about their health, the firm says users can explore the genetics behind why they may be a more frequent smoker, how they metabolise caffeine and their body's response to diet and exercise.
They can see information about the genetic basis of traits such as hair colour, freckling, height and hair loss.
The service also includes a "full genetic ancestry report" allowing people to trace their family's genetic roots and "potentially discover and communicate with new relatives", according to 23andMe.
Chief executive Anne Wojcicki said: "23andMe's mission is to ensure that individuals can personally access, understand and benefit from the human genome.
"The UK is a world leader in genomics and we are very excited to offer a product specifically for UK customers."
The firm says on its website that it is "committed to maintaining the security and confidentiality of your personal information" and has put in place security measures to help protect against the "loss, misuse or alteration of information under our control"
The service is formally launched in the UK today and is available for £125 including shipping.
Around 10,000 UK-based customers have already paid extra to have the kit delivered from the US.
Last year the US Food and Drug Administration (FDA) raised concerns about some of the suggested uses of the service.
In response to warnings in the US, 23andMe took "corrective actions" which authorities judged to be "adequate" but reports relating to health are not available to users in the US because they have not been cleared by the FDA.
A source at the Department of Health (DoH) said the product being offered in the UK has a CE mark - meaning it meets legal requirements - and added that 23andme is following principles set out by the Human Genetics Commission in 2010 on direct-to-consumer genetic testing.
A DoH spokeswoman said: "This Government is developing the use of genomics for patient care within the NHS.
"We welcome initiatives that help to raise awareness of genomics and those which enable people to take more interest in their personal health but we urge people to think carefully before using private genomic services as no test is 100% reliable."
The Medicines and Healthcare Products Regulatory Agency (MHRA), which oversees medicines and medical devices in the UK, said the range of conditions listed by 23andMe was "much broader" in the US.
The range of tests on offer here is different and "supported by a different level of evidence" and the countries regulate products differently, according to the MHRA.
23andMe is understood to be working with authorities in the US to get the products back on to the market there.
An MHRA spokesman said: "Products used in personal genome services are regulated by MHRA to meet minimum standards.
"People who use these products should ensure that they are CE-marked and remember that no test is 100% reliable so think carefully before using personal genome services."
Some experts expressed concern.
Professor Frances Flinter, of King's College London, said the UK has "excellent" genetics services, adding: "Genetic testing without the professional support of experienced staff may be less informative or even misleading."
Professor Shirley Hodgson, of St. George's Hospital, said: "This type of test is very open to misunderstanding. The results can indicate very slight alterations of risk for certain traits or diseases which can be misinterpreted unless explained in detail by a medical practitioner who understands such information."
Professor Tim Spector, of King's College London, who has worked with 23andMe, said: " I am in favour of any way to get the UK public more involved in science and genetics - and this is a great way to get educated in the power of genetics as well as its limitations.
" Like our knowledge of genetics - the implications of the results keep changing, so don't take the predictions too seriously."