It is not possible to compare the DNA profiles of two individuals and reliably confirm if they are first cousins.

Investigating if two people are related involves analysing a number of DNA markers that are inherited and determining how many of these markers the two people have in common. A statistical analysis will then report the most likely relationship given the DNA results. This is a very reliable way of identifying close biological relationships, but normal variation in the inheritance of these markers means that it is difficult to reliably distinguish first cousins from unrelated people.

Reputable DNA testing companies generally do not undertake first cousin analysis, testing just two people, because the results are very likely to cloud the matter rather than clarify it.

It may however be possible to investigate a first cousin relationship by testing other family members or by undertaking other types of DNA analysis. We would recommend that you call Cellmark free on 08000 362 522 for confidential advice about your particular situation.

Cellmark has been providing DNA relationship testing for 20 years!