There are many conditions which affect the outcome of a coin flip, these conditions are the force, the speed and angle of spin, height of the coin from the ground and which side of the coin is facing up to start with. These changes are significant enough to prevent a fifty-fifty probability.
The researchers showed that coin tossing isn't random; it's a measurable event that obeys the laws of physics just like everything else. If each coin has exactly the same initial conditions and exactly the same force then its spin will produce an even outcome of landing on heads or tails.
I wonder what the chance of a coin landing on it's side is? It can't be impossible, can it?