Direct-to-consumer (DTC) genetic testing companies give consumers easy access to their genetic data, specifically genotyping on genome-wide chips of up to 1 million variants. Estimates suggest that 26 million people had used online DTC companies such as Ancestry.com and 23andMe up to the end of 2018 (https://www.technologyreview.com/s/612880/more-than-26-million-people-have-taken-an-at-home-ancestry-test/). Whilst many purchasers are initially interested in ancestry testing, customers may then move on to analyse their genetic data for health [85], downloading their raw genotype data to explore in third-party interpretation programmes. These programmes are unregulated and differ in the genetic risks provided, the explanatory information provided, and the cautions given over interpretation. Some sites allow users to calculate polygenic risk scores; for example, Impute.me (https://www.impute.me/) shows users where their polygenic risk score lies against a population-specific distribution of scores. Allelica provides an online service calculating polygenic risk scores [86]. In direct-to-consumer genetic testing, MyHeritage (https://www.myheritage.com/health/genetic-risk-reports) provides polygenic risk scores on four traits, ‘for people who are of mainly European ancestry’. The most detailed assessment of PRS in a DTC setting is from 23andMe, whose white paper presents their epidemiological modelling and
