Craniopagus twins conjoined twins develop inutero remains unclear. Embryologists have traditionally attributed identical twinning as "splitting or fission" of either the inner cell mass of pleuripotential cells or early embryonic disc at 13–14 days of gestation just before the primitive streak. Some theorists suggested that conjoined twins develop as a result of the failed fusion of a single fertilized ovum. However a new hypothesis suggests that cranial fusion occurs between two separate embryos before the end of the 4th week of gestation. This can happen because the cranial neuropore is still open, which is responsible for the ultimate fusion and formation of
Barbi Twins been searching for him since 2008. Their search remained ongoing as of 2014. Barbi Twins Shane and Sia Barbi (born April 2, 1963), popularly known as The Barbi Twins, are identical twins, cover models, co-authors, and spokespersons for animal rights advocacy. Shane and Sia began modeling at the age of seven when they posed for a layout in the Sears mail-order catalog. As adults, their career has included fashion and mainly pin-up modeling. The "Los Angeles Times" did a cover story about the Barbi Twins when their billboard went up on Sunset Boulevard in 1989 immediately catapulting them to worldwide