Once every 100,000 births or so twins are born with bodies that are joined. These conjoined twins may share internal organs and may or may not be surgically separated.
The first case of such twins widely known were the brothers Chang and Eng, who were born to Chinese parents in what was then called Siam (now called Thailand). Back then, it was not possible to safely separate the two boys, so they grew up attached at the chest with a piece of cartilage. Their two livers were also joined.
When the brothers were 18 years old, they were swimming (together—obviously, they had to do almost everything together), and a British merchant saw them. He paid the boys and their family to take the twins on a world tour, to be exhibited as a curiosity.
Eventually their contract with the merchant ran out, and Chang and Eng decided to move permanently to the United States. They bought a farm in North Carolina, took the last name “Bunker,” and became U.S. citizens. They bought some slaves to work the farm, and they even married two sisters! Between them, Chang and Eng had ten children, some of whom ended up fighting for the Confederacy in the Civil War.
Because Chang and Eng were so famous, conjoined twins have often been called “Siamese twins,” even though of course other conjoined twins were born elsewhere. Interestingly enough, when they were in Siam, the twins were called “the Chinese twins” because of their Chinese parents.
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