Yasuda and Morton (1967) traced the history of the use of surname models for the study of human inbreeding to George Darwin's (1875) article in the Journal of the Statistical Society. Darwin's father, the famous naturalist Charles Darwin, and his mother, a member of the Wedgwood family of china pottery fame, were first cousins. Darwin was interested in the possible deleterious effects of consanguinity of parents and he wanted to know the frequency of cousin marriages in England. He therefore sought data on cousin marriages and on marriages between persons of the same surname in various sources such as Burke's Peerage and the Pall Mall social register. He then followed an ingenious line of thinking to estimate the proportion of marriages between first cousins. He reasoned that marriages to a person of the same surname who was not a first cousin would be proportional to the frequency of the surname in the population. This would be frequent only for common surnames. The Registrar General (1853) had published the frequency of the 50 most common surnames in the marriage registers and from the sum of the squares of these frequencies (0.0009207) Darwin estimated that marriages between unrelated persons of the same surname would be not much different from one per thousand. The excess over this of marriages of persons of the same surname was ascribed to cousin marriages and this was divided by the fraction of cousin marriages that were same-name marriages to give the number of cousin marriages in the population.