The human genome is about 3.4B base pairs (G-C, A-T). The specific DNA used for genealogical matching is 700K base pairs. So the testing companies are only usin

The human genome is about 3.4B base pairs (G-C, A-T). The specific DNA used for genealogical matching is 700K base pairs. So the testing companies are only using 0.02% of your DNA, hardly enough to compromise you. Furthermore, the matching process is based on SNPs (Single Nucleotide Polymorphism) and STRs (Short Tandem Repeat) in the "junk" DNA section, which constitute 92% of your DNA, and is distinct from the coding DNA that contains health traits, among others. So, not much to worry about.