Here's an interesting article comparing the pull out method to condom use. It claims the pull out method is nearly as good as a condom, which goes contrary to what you hear most people say. Also, most people think that precum is teaming with sperm. The article claims that this is not true. Is it legit? Read and decide. I don't have the medical expertise to say one way or the other.
http://www.alternet.org/module/printversion/140794