Conjoined twins
From Wikipedia,
Conjoined twins are identical twins whose bodies are joined in utero. A rare phenomenon, the occurrence is estimated to range from 1 in 50,000 births to 1 in 100,000 births, with a somewhat higher incidence in Southwest Asia and Africa. Approximately half are stillborn, and a smaller fraction of pairs born alive have abnormalities incompatible with life. The overall survival rate for conjoined twins is approximately 25%. The condition is more frequently found among females, with a ratio of 3:1.
Two contradicting theories exist to explain the origins of conjoined twins. The older theory is fission, in which the fertilized egg splits partially. The second and more generally accepted theory is fusion, in which a fertilized egg completely separates, but stem cells (which search for similar cells) find like-stem cells on the other twin and fuse the twins together. Conjoined twins share a single common chorion, placenta, and amniotic sac, although these characteristics are not exclusive to conjoined twins as there are some monozygotic but non-conjoined twins that also share these structures in utero.
The most famous pair of conjoined twins was Chang and Eng Bunker (In-Chan) (1811–1874), Thai brothers born in Siam, now Thailand. They traveled with P.T. Barnum's circus for many years and were billed as the Siamese Twins. Chang and Eng were joined by a band of flesh, cartilage, and their fused livers at the torso. In modern times, they could have been easily separated.[5] Due to the brothers' fame and the rarity of the condition, the term "Siamese twins" came to be used as a synonym for conjoined twins
List of notable conjoined twins
Born 19th century and earlier
• Mary and Eliza Chulkhurst (1500–1534, also known as the Biddenden Maids) from England. They are the earliest set of conjoined twins whose names are known.
• Lazarus and Joannes Baptista Colloredo (1617-164-?)
• Helen and Judith of Szony (Hungary, 1701–1723)
• Chang and Eng Bunker (1811–1874), from Thailand (formerly Siam), joined by the areas around their xiphoid cartilages, but over time the join stretched; the expression Siamese twins is derived from their case
• Millie and Christine McCoy (July 11, 1851 - October 8, 1912) were American conjoined twins who went by the stage names "The Two-Headed Nightingale" and "The Eighth Wonder of the World".
• Giacomo and Giovanni Battista Tocci (1875?-1912?)
Born 20th century
• Daisy and Violet Hilton of Brighton, England (1908–1969), actresses, appeared in the movies Freaks and Chained for Life.
• Lucio and Simplicio Godina of Samar, Philippines (1908–1936)
• Masha and Dasha Krivoshlyapova of Moscow, Russia (1950–2003), rarest form of conjoined twins, only known case of dicephalus tetrabrachius tripus (two heads, four arms, three legs).
• Ronnie and Donnie Galyon of Ohio (1951–), currently the world's oldest living conjoined twins, Omphalopagus.
• Lori and George Schappell born September 18, 1961 in Reading, Pennsylvania, American entertainers, craniopagus.
• Ladan and Laleh Bijani of Shiraz, Iran (1974–2003); died during separation surgery in Singapore.
• Viet and Duc Nguyen, born on February 25, 1981 in Kon Tum Province, Vietnam, and separated in 1988 in Ho Chi Minh City. Viet died on October 6, 2007.
• Abigail and Brittany Hensel are dicephalic parapagus twins born March 7, 1990 in Carver County, Minnesota.
Born 21st century
• Carmen and Lupita Andrade-Solis, born in Mexico in 2000 with Dicephalus Tetrabrachius Dipus (2 heads, 4 arms and 2 legs). Separation was not possible.
• Carl and Clarence Aguirre, born vertical craniopagus in Manila on 21 April 2002, successfully separated in 2004.
• Kendra and Maliyah Herrin, ischiopagus twins separated in 2006 at age 4.
• Anastasia and Tatiana Dogaru, born outside Rome, Italy on January 13, 2004. As Craniopagus twins, the top of Tatiana's head is attached to the back of Anastasias's head.
• Lakshmi Tatma (born 2005) was an ischiopagus conjoined twin born in Araria district in the state of Bihar, India. She had four arms and four legs, resulting from a joining at the pelvis with a headless undeveloped parasitic twin.
• Krista and Tatiana Hogan, Canadian twins conjoined at the head. Born October 25, 2006. Share part of their brain and can pass sensory information and thoughts between each other.
• Trishna and Krishna from Bangladesh were born in December, 2006, Craniopagus twins, joined on the tops of their skulls, and sharing a small amount of brain tissue. In 2009, they were separated in Melbourne, Australia.