Myrtle Corbin was born with four legs.
Dipygus is an extremely rare birth defect. At some point in foetal development the torso splits in two. Above, a single body; below, two parallel bodies, with all external features and internal organs duplicated. I’m not entirely clear how similar dipygus is to a conjoined or parasitic twin; some sources link the two but others describe dipygus separately. Most children born with dipygus do not survive, but Myrtle Corbin thrived.
Born in Tennessee in 1868, Corbin had four legs: two small central legs, one outside leg with a club foot, and another outside leg. In fact, her whole body split right above the waist. Corbin had two pelvises. She could kick her smaller legs but mainly got around on the larger two. In 1881 she joined a sideshow and spent several years being gawked at for money.
Corbin married and, in 1887, complaining about pain in her left side, a doctor discovered that she was pregnant. Having two pelvises, it turned out, meant that she also had two uteruses; this pregnancy was on the left one. When she was told this, Corbin famously said “if it had been in my right side I would come nearer believing you are correct.”
Because she was in considerable pain Corbin received a medical abortion that time, but she went on to have five children – all healthy and hearty. She died in Texas in 1928; her coffin was sealed up with concrete to dissuade potential graverobbers.