Kidneys, ribs and even testicles: the extra body parts you might not know you have

Around 1% of the world's population are born with extra fingers or toes. Thiti Sukapan/ Shutterstock

Thanks to millions of years of evolution, the human body has become well versed in its developmental processes. Most of the time, it gives us the correct number of organs and structures that we need to function. But sometimes, hiccups in this process mean people end up with extras.

Accessory teeth, fingers, toes and nipples are actually surprisingly common.