In 1955 he was bitten by a snake, refused treatment, and died. The only other possibility I could think of was conjoined twins. Despite the terminology, twin classification is actually pretty simple. It's based on placental anatomy, which is important because some types of placental development give rise to more abnormalities than others. The issue with identical twins is the number of chorions and amnions, the two layers of the sac surrounding the fetus.
Monochorionic twins have ten times the risk of abnormality that dichorionic twins do.
The issue is implantation. If they implant at adjoining spots, there's a chance one twin will steal resources from the other. Cecil Adams can deliver the Straight Dope on any topic. For book details click here. Inc. All rights reserved.