This installment of National Geographic's popular series In the Womb follows the embryonic and fetal journey of one of nature's most fascinating reproductive miracles—identical twins. Witness key moments—from the spontaneous splitting of a single fertilized egg into identical twins to the major milestones of twin fetal development, ending with their dramatic births. Along the way, learn how skin color is formed; what happens when aberrations in early development occur, producing conjoined twins; and how twins with ambiguous genitalia (hermaphrodites) can develop. Meet a pair of identicals who were separated at birth and met for the first time four decades later. Then, see dramatic 4-D ultrasound images of twins interacting in the womb in real time.