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  • In Tight Spaces, Sperm Slither Rather Than Shimmy

    In Tight Spaces, Sperm Slither Rather Than Shimmy

    Sperm usually swim in a 3D shimmy: a spiral wave travels down the whippy flagellum and rotates its head in a circle around its long axis. That “bulk swimming” is fine most of the time, but it isn’t a great option when a sperm cell gets close to a surface. That’s when they switch to…


  • Sex Isn’t As Risky As You Think It Is

    Sex Isn’t As Risky As You Think It Is

    People are crap at estimating risk. They’re scared of flying, for example, even though it’s far less likely that their metal sky-bird will crash and burn than their car will get crushed by a truck on the way to the airport. Combine that with a tendency to get judgey about sex, and you’ll find attitudes…