23andMe genotypes specific DNA locations differing between people for ancestry and health reports. Ancestry composition traces origins to 0.1% across 4500+ locations including counties. Genotyping skips full sequencing of every DNA letter. Ethnicity affects relevance of every genetic health report. BRCA1/BRCA2 report tests only 44 variants missing majority in most ethnicities. BRCA variants tested link to higher breast, ovarian, prostate, pancreatic cancer risks. Absent tested variants do not rule out other cancer risk mutations. PGS test reports FDA-reviewed and un-reviewed health predispositions plus carrier status. Test ignores current health status and forbids medical decisions. Carrier reports detect one variant copy but ignore two-copy presence or future disease risk. Saliva samples from most adults yield accurate genotyping. Lab processes samples in weeks for online results. 23andMe sold 12 million kits prioritizing privacy. Ethnicity-specific variant gaps limit report utility across groups.