Conjoined twins Conjoined twins Conjoined twins are identical twins joined "in utero". An extremely rare phenomenon, the occurrence is estimated to range from 1 in 49,000 births to 1 in 189,000 births, with a somewhat higher incidence in Southwest Asia and Africa. Approximately half are stillborn, and an additional one-third die within 24 hours. Most live births are female, with a ratio of 3:1. Two contradicting theories exist to explain the origins of conjoined twins. The more generally accepted theory is "fission", in which the fertilized egg splits partially. The other theory, no longer believed to be the basis of conjoined twinning,
Tarzan and the Tarzan Twins it features Tarzan's first meeting with Doctor Karl von Harben, with whom he is already acquainted in "Empire". Because "Twins" is a children's book, however, it is customarily omitted from listings of the main Tarzan series. Thus "Tarzan, Lord of the Jungle" is generally considered the eleventh Tarzan book rather than "Twins". Two schoolboys, Dick and Doc, are cousins who resemble each other because their mothers are twins. As Dick is also related to Tarzan through his father, they become known as the Tarzan Twins. Invited to visit Tarzan's African estate, they become lost in the jungle and are imprisoned