DNA testing has gained widespread use as a tool for checking whether someone is related to you. It requires a subscription to a web site, the purchase of a test kit and the careful collection of a small amount of saliva. You or someone you nominate can study the matches that are revealed.
DNA is clearly a valuable research tool, but it should be used with care. It can find matches only to current subscribers to the same web site who have also taken a test. So it will not find all your relatives.
It will reveal many matches that you cannot immediately explain and some that you will never be able to. And of course it might reveal illegitimacy or adoptions that older members of your family have never revealed and might find very embarrassing. You might uncover people who are unwilling to be in contact you, perhaps because they are estranged from the family or were mistreated in the past.
DNA testing is widely advertised, which encourages users to subscribe a web site and take a test. They often have no experience of genealogy, and may struggle to make sense of what they find.
But it can shed very useful light on relationships you have discovered using conventional genealogical research but for which you lack convincing proof. It can also lead to dialogue with relatives you have not previously contacted – this can be enjoyable and productive.
So use DNA testing wisely and carefully.