Fun And Trivial, Not Science
Ancestry tests are more fun and trivial than an exact science. It is fun to discuss what percentage you are of particular groups of people, but it won’t provide you much true scientific meaning. We have thousands of ancestors, and it is a very complex process to trace them.
If you find yourself in the situation that requires a paternity test, this is also done through DNA testing and comparison. Many non-invasive prenatal paternity tests can be done that are highly accurate and also very safe.