Commentary: A Darwin family concern

‘I’m not quite sure that it’s a good thing for cousins to marry’, remarks Dr Crofts in Trollope’s The Small House of Allington, published in 1863. ‘They do, you know, very often’, he is reminded, ‘and it suits some family arrangements’. 1 To be sure, the doctor had a personal interest in the matter. A young woman he hoped to marry had just become engaged to her cousin. However, Dr Crofts was talking as a responsible medical man. The British medical press was raising questions about the risks to offspring of cousin marriages, 2,3 and a bright young doctor would have been familiar with the professional debates. (And in the end he gets his girl.) Charles Darwin had picked up on these concerns very early. He was worried about heredity and also about the consequences of cousin marriage. Shortly before his own marriage to his first cousin, Emma Wedgwood, he had consulted a new book, Alexander Walker’s Intermarriage: Or the Mode in Which, and the Causes Why, Beauty, Health, and Intellect Result from Certain Unions, and Deformity, Disease and Insanity from Others (1838). It touched a sensitive nerve. His Darwin grandmother, the wife of Erasmus Darwin, was addicted to gin and suffered from bouts of madness. Charles Darwin’s own mother, unwell throughout his childhood, had died from an agonizing stomach ailment, probably peritonitis, at the age of 52 years. Charles was 8 years old when she died, and as an adult he was obsessively concerned with his own ill-health, particularly the recurrent stomach complaints that recalled his mother’s fatal illness. Both his mother and Emma were Wedgwoods, and the Wedgwoods were notorious for their ill-health. 4 Whenever one of his children fell ill, Charles was inclined to see the same symptoms in himself, and to worry that it exposed a family propensity. Or were the frequent illnesses of his children, and the health problems of the Wedgwoods, perhaps the consequence of cousin marriages? 5 This was a growing concern in scientific circles in Britain in the 1860s. ‘In many families, marriages between cousins are discouraged and checked’, Francis Galton noted in 1865. 6 Charles Darwin’s son George published an early paper recommending that cousin marriage should be avoided. 7