Mermaid Baby

A popular term for a rare—1:100,000 births—congenital defect in which the legs are fused together, simulating a mermaid’s tail. Because it is often associated with urinary tract defects—kidney and bladder—as well as other organ defects, most infants die shortly after birth. It is 100 times more common in identical twins and is linked to defective in utero development of the lower abdominal aorta. The preferred medical term is sirenomelia