It might seem like the perfect birthday present a DNA test you can do at home to find out a bit more about where you come from. (Subscribe: https://bit.ly/C4_News_Subscribe)

More than 26 million people have done tests with the leading companies worldwide. But as the database gets bigger so does the number of surprises thrown up. Secrets that once went to the grave, are now being revealed years later.

In the first of our series looking at DNA , we hear from people for whom a simple test has revealed more than they bargained for.

This film was made by Fran Robertson.

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