Here is a thought! Ultralite, you could have 100% effective, risk free birth control by practicing abstinence until you find a woman who actually doesn't want kids and has taken her own permanent steps!
because what you're saying is "I really really don't want kids. But sex is important enough to me that I'm willing to gamble when the odds are 85% in my favor" aaaand, you're gambling with someone else's life! (I'm referring to the potential child, not the woman)