Before epilepsy was understood to be a neurological condition, people believed it was caused by the moon, or by phlegm in the brain. They condemned seizures as evidence of witchcraft or demonic possession, and killed or castrated sufferers to prevent them from passing tainted blood to a new generation.
Just depends on how you define free will, what you take from that definition, how you approach the randomness of quantum physics, and how you feel about the boundary conditions of the universe.