natural birth control

"Coitus Interruptus Erroneous: Would You Believe That Pulling Out Actually Works?"
http://www.alternet.org/story/140794/?comments=view&cID=1243202&pID=1242...

Withdrawal Method Finds Ally
http://www.nytimes.com/2009/07/21/health/21cond.html?_r=1

Critique by sexologist:

In the 2002 National Survey of Family Growth (NSFG), withdrawal appeared to be almost as effective as condoms during typical use. However, in the 1995 NSFG, withdrawal was considerably less effective than condom use.