The Haarket twins, joined by a pipe.

Hans and Slami Haarket, born in Knoxville of Norwegian parents one sweltering August day in 1973, have been joined since birth by a metal tube connecting their hands. Doctors were mystified by the phenomenon and do not know how it happens. “Metal tubes do not usually occur naturally in the uterus. That is to say, unlike babies, it is uncommon for a metal tube to grow in the uterus. It is possible the mother swallowed the tube at some point, but there is a rare condition, happening in one in three billion births, where a metal tube which formed in the uterus becomes attached to the fetus that is developing at the same time,” explained Dr. Fenton Valentino, an obstetrician practicing at Park West Medical Center. Their 30th birthday is coming up, an event heralded as the first such time subjects with this condition have lived that long. The tube is apparently made of a titanium alloy. Doctors are researching how to remove the tube without harming either man using a delicate experimental procedure.