> this does not increase that probability very much That depends[1] strongly on what question you are asking. Matching an unknown sample against a small number

> this does not increase that probability very much That depends[1] strongly on what question you are asking. Matching an unknown sample against a small number of suspects is a very different question than searching a database with millions (or billions) of records. The latter is almost guaranteed[2] to return false positives. > it massively improves the odds of finding criminals That's a strong claim that requires equally strong evidence. [1] https://www.schneier.com/blog/archives/2008/09/dna_matching_an.html https://www.schneier.com/blog/archives/2008/09/dna_matching_... ( http://archive.li/M0SeV http://archive.li/M0SeV ) [2] https://en.wikipedia.org/wiki/Birthday_problem https://en.wikipedia.org/wiki/Birthday_problem