The Mysteries of Twins

http://www.washingtonpost.com/wp-srv/national/longterm/twins/twins2.htm

twins are the perfect people on whom to test hypotheses about what is molded by life's pressures and what is inborn...on average, identical twins tend to be around 80 percent the same in everything from stature to health to IQ to political views...evidence from the comparison of twins raised apart points rather convincingly to genes as the source of a lot of that likeness...

James Arthur Springer and James Edward Lewis, had just been reunited at age 39 after being given up by their mother and separately adopted as 1-month-olds.they had each married and divorced a woman named Linda and remarried a Betty. They shared interests in mechanical drawing and carpentry; their favorite school subject had been math, their least favorite, spelling. They smoked and drank the same amount and got headaches at the same time of day.

another set of twins, Oskar Stohr and Jack Yufe.
when the twins were reunited in their fifth decade they had similar speech and thought patterns, similar gaits, a taste for spicy foods and common peculiarities such as flushing the toilet before they used it.

studies have been done to show that identical twins are roughly 85 percent similar for IQ, fraternal twins about 60 percent...On average, identical twins raised separately are about 50 percent similar -

twins tell uncanny stories of wordless understandings, of moments of grief or joy communicated at a distance without benefit of a phone,

a woman named Gilia Angell recalls wandering into the St. Patrick's Cathedral gift shop in New York and buying a postcard of an airbrushed Jesus, which she mailed to her twin sister in Olympia, Wash. A few days later, she says, a letter postmarked the same day arrived from Olympia. Enclosed was a refrigerator magnet "with the same filmy airbrushed picture of Jesus!"

Victor McKusick was treated at Massachusetts General Hospital for an infected arm,...Victor developed a dental abscess. His brother, sailing up from Maine to join him, had to make an emergency shore call after developing the same problem

Scientists in Richmond have shown that correlations for marijuana and cocaine use are nearly the same between fraternal and identical twins, suggesting that social environment is the main cause of drug experimentation. But the identical twin of a drug addict is far more likely to be an addict than is the fraternal twin of an addict.