Originally Posted by NateR
The doctor who delivered them says they are fraternal, which means that they had two separate placental sacks. If they were identical then there would have only been one placenta. A DNA test would determine that as well, since identical twins would have identical DNA and fraternal twins would each have unique DNA. However, I think that after 35 years even identical twins' DNA would have changed enough that each would be unique.
Identical twins can have separate placentas and amniotic sacs. It all depends on when the split occured exactly.