This Christmas it's likely that more people than ever before will spit into a tube, or swab some cheek cells and send the result off for DNA analysis. Millions in the US have already done it, and the craze is spreading. But what happens when you find out a lot more than you were expecting?
Three years ago, Jenny decided to take a DNA test "just for fun". The youngest of five children, she had always been intrigued by stories about her ancestors. As a teenager she loved looking at old photographs with her grandfather and over the decades she had painstakingly pieced together her family tree.
Once her children were grown and she had more time on her hands, Jenny, a freelance writer from Connecticut, began going to genealogical conferences and workshops to improve on her methodology. "Everyone was talking about doing these DNA tests but I wasn't keen - it all sounded very scientific and I have no head for that."
Yet Jenny was curious to see what the test might reveal about her ethnic background, so she sent off for a kit and gave it a go.
There were no surprises when the results revealed her heritage as largely British, including Scottish, with a smattering of genes from Scandinavia. "Nothing exotic," she laughs.