Why is marrying cousins wrong

His parents were first cousins twice over! World globe An icon of the world globe, indicating different international options. Get the Insider App. Click here to learn more. A leading-edge research firm focused on digital transformation.

Good Subscriber Account active since Shortcuts. Account icon An icon in the shape of a person's head and shoulders. It often indicates a user profile. Log out. US Markets Loading H M S In the news. The Missouri outlaw married his first cousin Zerelda "Zee" Mimms in at the height of the James-Younger gang's reign.

They had two children and remained together until Jesse's death, aged 34, 12 years later. The science fiction author of The Time Machine and The War of the Worlds married his first cousin Isabel Mary Wells in but left her after three years to marry one of his students, with whom he had two children. The American gothic poet secretly married his year-old first cousin, Virginia Eliza Clemm, in She died of tuberculosis in In Bach married his second cousin Maria Barbara Bach and had seven of his 20 children with her.

The Birmingham MP married his first cousin, Rifat, when he was in his twenties. They had a child — now a teenager — but separated in The naturalist, whose work forms the basis for contemporary evolutionary theory, married his first cousin Emma Wedgwood in They had 10 children, to whom he was a devoted father.

Join thought-provoking conversations, follow other Independent readers and see their replies. In other words, in societies in which people frequently married their relatives, intermarrying showed a stronger link to having more children. There could be many explanations for the different effects of inbreeding shown in the two kinds of societies. Perhaps the best explanation, Bailey said, may be that non-foraging societies are more likely to have heritable resources, such as wealth or livestock, so a tight-knit family group might be more likely to defend each other and their shared resources.

By contrast, in a foraging society, it might make more sense to be part of a much larger, interconnected group, since there are few or no resources to be inherited. It's tempting to think that people in agricultural societies might intermarry purely out of convenience, since they're less likely to encounter new people as often as hunter-gatherers might. But that's not the case, Bailey said. Agricultural societies tend to be much larger than hunter-gatherer ones, so if anything, the reverse might be expected.

Another factor to consider is that in established, highly stratified societies, members of the upper class or royalty would have intermarried simply to preserve their social status. They may have also had more surviving children because they had greater resources for supporting these families.