Erin and Abby Delaney were born in joined at the head -- a rare early stages of development, an embryo only partially separates to form two babies. Conjoined twins are rare, occurring in about one out of every , live births, experts say. . The two Indonesian twin baby girls were successfully separated in a. Apr 19, - The Incredible Story Of Conjoined Twins Abby And Brittany Hensel [VIDEO] Each has her own head, but they share most everything else: torso, pelvis, legs, Basically, Abby and Brittany have two separate bodies that join at the ribcage. Each girl controls one half of their body, so even the simple act of.