Caution should always be taken before pursuing an answer to a genealogical question. Ask yourself (or your relative) before diving into the research whether you really want to know the answer, and whether you think you are prepared for it. Just because you as a genealogist may be prepared for the result does not mean everyone in your family will be.
This is as true with DNA evidence as it is with any other type of genealogical evidence. Just as a census record or birth certificate can reveal a family secret, so can the results of a DNA test. The Genetic Genealogy Standards, for example, make clear that unexpected results can occur:
12. Unexpected Results. Genealogists understand that DNA test results, like traditional genealogical records, can reveal unexpected information about the tester and his or her immediate family, ancestors, and/or descendants. For example, both DNA test results and traditional genealogical records can reveal misattributed parentage, adoption, health information, previously unknown family members, and errors in well-researched family trees, among other unexpected outcomes.