Personal genomics services are becoming popular for genealogical or ancestry-tracing purposes (see, for example, go.nature.com/scbwci). But this direct-to-consumer practice undermines promises of sperm-donor anonymity, which is still common in clinics in many countries (see also M. Angrist Nature 494, 7; 2013).

Adults conceived from donor sperm can now identify their biological fathers using DNA testing (see R. Lehmann-Haupt Slate, 1 March 2010). In doing so, they could be unwittingly infringing the gamete donor's constitutional right to privacy.

Companies selling personal genetic testing therefore have a responsibility to inform customers about the potential risk of privacy breaches, as do clinics accepting gamete donors.