When identical twins procreate with another set of identical twins, their offspring are both genetic siblings and social cousins.
2. The Japanese identical twins who were affectionately nicknamed Kinsan Ginsan released a rap song when they turned 100 years old in 1992.
3. On an average, identical same-sex twins live longer than fraternal same-sex twins, who in turn live longer than the general population.
4. In 2009, despite having DNA evidence of the suspect, German police could not prosecute the perpetrator of a $6.8 million jewel heist because the DNA belonged to identical twins (Abbas and Hassan O), and there was no evidence to prove which one of them was the culprit.
5. The original "Siamese Twins" (Chang and Eng Bunker) fathered a total of 21 children, and their descendants now number more than 1,500.
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There lived twin brothers (Knipe brothers) who stood over 7'2" tall in the 18th century. They toured London in 1784 and 1785.
7. A pair of twins were separated at birth in Ohio. When they both met, they found they had a lot more in common than their DNA. Both were named James by their families, married and divorced women named Linda, remarried to women named Betty, had sons a named James Allan and James Alan, and dogs named Toy.
8. In 2015, astronaut Scott Kelly became even younger than his elder twin brother (who is also an astronaut) Mark Kelly (born 6 minutes before Scott), by 3 milliseconds after the completion of his one year mission on the International Space Station.
9. A set of British twins separated at birth and raised by different adopted parents, fell in love and got married only to realize that they were brother and sister.
10. Young children, especially twins, will often develop their own language that they can understand but is unintelligible to any adult observers.
11Lina Hamilton and Leslie Hamilton
Scenes in the movie Terminator 2, where Sarah Connor and the T-1000's facsimile of her are in the same shot aren't CGI. Rather, it is Lina Hamilton and her non-actress identical twin sister, Leslie Hamilton, who acts as a very realistic body double.
12. There are actually seven different types of twins: Identical, Fraternal, Mirror-Image, Polar Body (Half Identical), Mixed Chromosome, Superfecundation, and Superfetation.
13. Tom Berenger once owned a restaurant called Twins on the Upper East Side, where the waitstaff consisted of 29 sets of identical twins.
14. Fields' disease is considered the rarest known disease in the world, with only two cases diagnosed (among two twin girls named Catherine and Kirstie Fields). It causes progressive muscular degeneration, and that's about all we know. Doctors concluded that "they were probably born with it."
15. When one of the Siamese twin Daisy Hilton died, her sister Violet remained alive and attached to her for several days before they were both found dead.
16Krista and Tatiana Hogan
There exists a case of conjoined twin girls named Krista and Tatiana Hogan, who are connected at the thalamus. They can hear each other's thoughts and see through each other's eyes.
17. Heteropaternal superfecundation is a rare medical scenario whereby twins can be born of two separate biological fathers.
18. Sideshow performer Francesco Lentini was born in Sicily in 1889 with 3 different length legs, 4 feet, and 2 genitals - a result of a partially absorbing his conjoined twin. He married, had 4 children, and lived to be 85. His photo is on the back cover of Alice In Chain’s self-titled album.
19. When identical twin basketball players Brook and Robin Lopez were both playing for NY-based teams, they considered living together. They then decided against it because their cats didn't get along.
20. The "first Siamese twins" (Chang and Eng Bunker) lived separate lives and would alternate every 3 days between their homes and families. They were only 3/4 Chinese.
To tell twins apart, look at their belly buttons. It's the one thing that's not affected by genetics.
22. A Vanishing Twin is a fetus in a multi-gestation pregnancy in which a twin dies in utero and is either completely or partially absorbed by their twin. Occasionally the dead fetus will be flattened by their growing twin into a parchment-like state known as Fetus Papyraceus.
23. Conjoined twins occur once in every 200,000 births, and conjoined triplets and quadruplets are so rare there are no confirmed cases. It is slightly more common, though, to have twins (conjoined or not) and an extra fraternal triplet known as a "pair and a spare".
24. ATL twins from the movie Spring Breakers live a similar life as shown in the movie. They live like one person. They share the same bed, wear matching outfits, and sleep with the same girls.
25. Swedish ice hockey player Henrik Lundqvist started playing the goaltender position because his younger twin brother, Joel, volunteered him by raising his hand for him at a youth practice.