It's an utterly ridiculous idea. We aren't born Muslim, or Jewish, or Christian, or anything else. Do we instinctively know the five pillars of Islam, the fact Jesus died for our sins, or any stories from the Old Testament? No. We learn them. We hear of religious ideas as we grow, and choose to (or are indoctrinated into) following them. Even if you can argue that mankind is naturally drawn to believe in a higher being, how on earth is that equivalent to Islam? Islam is more than that - plenty of religions over thousands of years have shared vague connections regarding God. Yes, we might be drawn to believe in a higher being, but are we drawn to follow Sharia law? It's easy to say "we're born pure" and that we're born Muslims, but there are absolutely NO facts to back that up, at all. If you watch any toddler go about his or her buisiness who hasn't been indoctrinated with Muslim ideas, the last thing you'd ever think was that they were Muslims! You'd think that they were a lot of work and maybe pretty cute, but they wouldn't be Muslims. They might BECOME Muslims if they happened to be in a Muslim family, but they could just as well end up as Hindus if they were brought up in a Hindu family. And then if they converted to Islam later? They'd have converted, not reverted, because they were NEVER Muslims in the first place.