No one can power swim ALL the time!

Sperm have a reputation for being speedy little swimmers. But did you know that for the most part, the little tadpoles spend life in the testicles chillin’ out, doing the backstroke? It’s only once a sperm finds itself inside a vagina that it takes off at Michael Phelps pace.

Now you know!


  1. Milan says:

    Is this because the sugar-containing fluid that the spermatozoa metabolize hasn’t been mixed with the actual gametes prior to ejaculation?

    • nadinethornhill says:

      Apparently, it’s because while the alkaline environment of semen make sperm dozy and slow, the acidic environment of the vagina neutralizes everything and perks them right up.