What causes a Phobia?
Phobias are usually caused by a traumatic thing in their childhood or later on in life. For example somebody with arachnophobia (fear of spiders) might have had a spider crawl on them and try to bite them. This is a good way for somebody to get arachnophobia. There's a myth saying that children get their parents phobias passed down to them. But like I said it is a myth and every being on earth has a different phobia then others.