health

Estimates vary somewhat, but most researchers think that conjoined
twins occur once in every 33,000–165,000 births; however, 40–60 percent
of conjoined twins are stillbirths. In the United States, one in every
200,000 live births is a set of conjoined twins.
Male conjoined twins are more likely to be stillbirths. Conjoined
twins that are born alive are three times more likely to be females.
Conjoined twins are more common in India and Africa than in
Europe or North America. The reasons for this difference are not
known.

Chang and Eng

Chang and Eng Bunker (1811–1874) were conjoined
twins born in 1811 in Thailand (formerly
called Siam), for whom the term “Siamese twins,”
a term that is no longer culturally accepted, was
coined. Joined at the breastbone by a band of
cartilage, their vital organs functioned independently;
they could have been easily separated if
modern surgical techniques and equipment had
been available.
Like some other nineteenth-century conjoined
twins, Chang and Eng were discovered by a
British business promoter in 1829 and exhibited
as a medical curiosity. They later joined P.T. Barnum’s
traveling circus. They left the circus in
1839, settling in North Carolina. Taking the surname
Bunker, they became U.S. citizens and
married two sisters in 1843. The wives did not get
along, so the brothers set up separate households,
spending three days each week in each home.
Chang had ten children by his wife; Eng had
eleven.
The twins’ health declined in the early 1870s.
Chang died on January 17, 1874; Eng died an
hour later. They are subjects of several literary
works, the first was a short story by Mark Twain
called “The Siamese Twins.” With characteristic
humor, Twain suggested that the twins had
fought on opposite sides during the Civil War,
and that one was fifty-three years old while his
twin was only fifty-one.