The fastest cure for fundamentalism is a thorough reading of the Bible.
I have heard so many stories about people who became atheists by reading the bible. Often, I hear some Christians don't count the old testament as the 'bible'.
That part is complicated. They use the OT when it serves their purpose, i.e. Leviticus 18:22, but insist they're under a "new covenant" when it comes to dealing with Mosaic law. It's another one of those only pick the scriptures they like, and ignore the rest.