Is it safe, psychologically, to tell children the truth or let them decide which religion?

I think it might be a bit much responsibility and there might be many who'll try to influence your child's beliefs, possibly misleading them to suit their own best interest or beliefs... But I also think it might also be a lot of fun for a child to decide what they'd like to follow..They are after all, in their prime raw state of exploration and make believe.. As they grow older, we tend to take the make believe for being real.. And is harder to change. What do you say?