ABSTRACT
The detailed description of the birth of these biblical twins is by no means simple to understand. For instance, how are we to interpret the description of Jacob grasping the heel of Esau during birth1? The first, and most common, explanation for this situation is that these twins must have been monoamniotic, and as such, Jacob could grasp Esau’s heel in utero (Figure 68.1a). Yet, the biblical narrator meticulously describes the different phenotypes of the twins, which would suggest dizygotic twinning. The second possibility is that the twins were pseudo-monoamniotic (PMA), that is, the dividing membrane ruptured before birth (Figure 68.1b). However, the biblical scholar lbn Ezra commented, as early as the 12th century, that this is an extremely unusual event2. The fact that PMA twins were known in ancient times clearly suggests that the existence (with or without rupture) of an intertwin membrane was discussed in relation to the remarkable birth of Jacob and Esau. This chapter discusses this rare entity.
