How accurate are 23andMe's relationships predictions?

We’re extremely confident in the percentage of DNA you share with each of your DNA Relatives.

However, the predicted relationship we indicate in your results is just that -- an educated guess based on the information we have. The reason we aren’t always 100% confident in the relationship prediction is that some relationships involve similar percentages of shared DNA. For example, it’s sometimes difficult for us to distinguish between a first cousin and a first cousin, once removed.

Knowledge of your personal family history, conducting additional research, or perhaps starting a dialogue with your relatives may help you determine these relationships with greater certainty. Then, you can edit your relationship in the DNA Relatives feature based on your own knowledge.