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    The Rythmeter

    This simple scientific device will help you prevent unwanted pregnancies the natural, God-fearing way.

    Sarah Morgan
    by Sarah Morgan

    Community Contributor

    boingboing.net

    As you can see it is very easy to use! Although the man who created it, John C. Rock, went on to conduct the first trials of hormone-based birth control, so...it's possible he decided this was not a perfect system.

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