A rare condition, known as
situs inversus, is when a person has their major organs mirrored from their normal positions. So, for example, the heart would be on the right side of the body, or the liver and gall bladder are on the left side. It is a congenital condition (meaning it's tied to your genetics) that affects 1 in 20,000 people - including Spanish-born singer Enrique Iglesias.
Situs inversus is generally an autosomal recessive genetic condition, although it can be X-linked or found in identical "mirror image" twins.
