The inheritance of DNA from parents to children is perfect for exploring close family relationships through modern genetic techniques.
This property is not only useful for testing paternity it can also be extended for testing other family relationships, for example, whether or not two people are related as siblings (brother or sister) or whether two people are related as grandchild and grandparent.
As you would expect the more closely related you are the stronger the DNA test results will be but as relationships become more distant then the amount of directly inherited DNA two people share becomes diluted and testing methods start to loose their effectiveness. However, even with cousins there are DNA testing methods available to all of us that can be used to demonstrate a genetic family link or exclude the possibility of a true relationship.
In this section I explain some common approaches commercially available to private individuals who seek to test the existence of different types of family relationship other than paternity.