What cause disability

Good question. Let's see?

My father had drinking problems, ( never know if he did drugs) he's was women beater at the time.

My mom did cigarette ( don't know if that counts) she never drinks.

I got learning disability and deaf.

My mom side family has four people who is handicap ( deaf, can't talk so they used sign language, hard to walk sometimes)

I think it has something to do with my parents.