Before there was such a thing as humans and human history.

Leg-crossing is a natural, instinctual habit, not a learned one. In fact, the way you feel more comfortable when crossing your legs (right leg up vs left leg up) is determined to a point at a genetic level and inherited from parents to children.

Want to have a laugh with your (extended) family? Ask each member:

1. If their hair grows clockwise or counter-clockwise

2. If they can bend their tongue upwards, or not

3. If they can bend the sides of their tongue while keeping the middle down, turning their tongue into a tube, or not

4. If their little finger sticks out from the others when they keep their fingers stiff

5. If they have hair on the middle section of their fingers, or not

6. If they cross their arms with the right one above or the left one above

7. If they cross their legs with the right one above or the left

All those things are inherited.