Darwin Family Health Problems Linked to Inbreeding
Author: American Institute of Biological Sciences
Published: 2010/05/03 - Updated: 2026/02/06
Publication Type: Research, Study, Analysis
Category Topic: Offbeat News - Related Publications
Page Content: Synopsis - Introduction - Main - Insights, Updates
Synopsis: This research report details a peer-reviewed study appearing in BioScience (May 2010) by Tim M. Berra, Gonzalo Alvarez, and Francisco C. Ceballos that examined 25 families encompassing 176 children across the Darwin-Wedgwood dynasty. The findings provide statistical evidence connecting inbreeding coefficients to child mortality rates, validating Charles Darwin's own concerns about marrying his first cousin Emma Wedgwood. For anyone researching genetic health risks, family medical history, or hereditary conditions that affect both historically significant families and modern populations, this scholarly analysis offers documented evidence of how consanguineous marriages can influence childhood mortality, developmental abnormalities, and unexplained infertility - health concerns that remain relevant today for individuals tracking genetic predispositions - Disabled World (DW).
- Definition: Inbreeding Depression
Inbreeding depression refers to the reduction in biological fitness that occurs when closely related individuals mate and produce offspring. This happens because inbreeding increases the probability that offspring will inherit two copies of deleterious recessive alleles - harmful genetic variants that typically remain hidden when paired with functional copies from unrelated parents. The effects can manifest as reduced fertility, increased susceptibility to disease, lower survival rates, decreased growth, and various developmental abnormalities. While the severity varies depending on the species and the degree of relatedness, inbreeding depression is observed across virtually all sexually reproducing organisms, from plants to animals. The phenomenon is particularly important in conservation biology, where small, isolated populations face unavoidable inbreeding that can create a downward spiral toward extinction, and in agriculture, where breeders must carefully manage breeding programs to maintain hybrid vigor while fixing desirable traits.
Introduction
Charles Darwin's Family Health Blamed on Inbreeding
Inbreeding may have caused Darwin family ills - The Darwin/Wedgwood dynasty exhibits a link between inbreeding and child mortality.
Charles Darwin's worries about possible adverse effects of inbreeding in his family seem to have been justified, according to a study described in the May 2010 issue of BioScience. Darwin married his first cousin, Emma Wedgwood, and his mother, Susannah Wedgwood, was the daughter of third cousins.
The study, which extended to 25 families including 176 children, found a statistical association between child mortality and the inbreeding coefficient of individuals in the Darwin/Wedgwood dynasty.
Main Content
Charles Darwin demonstrated the phenomenon of inbreeding depression in many plants, and was aware of research into the effects of marriage between relatives on the health of resulting children. He feared that his marriage might have been responsible for some of his children's health problems and asked a member of Parliament to add a question about marriages to relatives to the British 1871 census form.
Three of Charles Darwin's 10 children died before reaching adulthood, one from childhood tuberculosis at age 10 and one from unknown causes as an infant. A third child, who died in infancy of scarlet fever, appears in a photograph to have developmental abnormalities.
Inbreeding is an important risk factor in a number of human diseases, including infectious diseases. The authors of the study, Tim M. Berra, Gonzalo Alvarez, and Francisco C. Ceballos, suggest that the expression of deleterious genes "produced by consanguineous marriages could be involved in the high childhood mortality experienced by Darwin progeny."
Furthermore, three of Darwin's six children with long-term marriages left no offspring. Unexplained infertility may also be a consequence of a consanguineous marriage. On the other hand, three of Darwin's sons were fellows of the Royal Society and were knighted by Queen Victoria.