Once your genetic information is out there, it’s difficult to undo. Also, once you know something about yourself, it’s impossible to forget. Revelations such as having different parents than you expected or finding unknown half-siblings are difficult to process at any age, but it’s particularly troubling for kids. However, you can always simply opt out of family matching features.
DNA tests offer a wealth of insights into your connections to family, history and geographical locations. They both entertain and encourage you to dig into what you know about yourself. The tests make great gifts to bring you closer to your family and involve you and your family in the development of a cutting-edge science at the same time. Beyond that, the information is extremely useful for adoptees, people looking for lost relatives, genealogists and for medical science.
In the case of a great-grandchild, or a great-great-grandchild, something even stranger can happen. Remember that a child will get half of their mother’s DNA, but there is never ever guarantee which 50%. The way it is chosen is fairly random, as far as scientists know. Take the example of the 100% Eastern European person. Their great-grandchild will inherit 50% of their DNA from their part-Eastern European parent, but there is a good chance that they won’t inherit all of the Eastern European DNA that they could potentially inherit. It’s possible for a person to share NO DNA with a great-great grandparent, even though there is a verified genealogical relationship.