Amongst the consequences of rising levels of genetic testing is the unwelcome revelation of “paternal discrepancy” — or the disclosure that a person’s father is not his or her biological father. Not only does this raise personal and social issues, but it also affects a person’s health, as he or she will have a different genetic profile than they thought. A UK-based research team has reviewed the literature on paternal discrepancy between 1950 and 2004 and found that rates range from less than 1% to as much as 30%. The generally accepted figure is about 4%. The rate appears related to early pregnancies, poverty, and co-habitation rather than marriage.