How many people can match a DNA profile?

It depends on the type and quality of the DNA profile, and how it has been interpreted.

A full, single-source DNA profile developed from a high-quality sample may be highly discriminating, meaning relatively few people would share the same combination of genetic characteristics. However, this does not mean the profile is unique to one individual.

In many cases, DNA results are more complex. Mixed DNA profiles, partial profiles, or low-level samples may be consistent with a larger number of individuals. The number of people who could match a profile can increase significantly where multiple contributors are present or where limited genetic information is available.

Statistical evaluation is used to estimate how common a DNA profile may be in the population. These calculations rely on modelling, assumptions, and population data, and can vary depending on how the analysis is performed.

Importantly, a “match” does not mean identification in the everyday sense. It indicates that a person’s DNA is consistent with the genetic characteristics detected, not that they are the only possible contributor.