Withdrawal and the Rhythm Method are constructed from basic FAIL particles. Anyone who uses these forms of so-called birth control are just admitting they expect to have a baby on a reasonable chance. You'd literally have to be stupid (i.e. religious or a backwoods hickfuck) to use these methods and seriously expect to avoid pregnancy.
Cutting the man's tubes is overall the safest, cheapest and most reliable form of birth control, when you consider ALL those aspects. If you want a kid after that, then just grab some of the thousands of children who are stuck in the foster-care and adoption systems. Your DNA isn't special.