Why Do Sperm Swim in Circles?
Susan S. Suarez

In my Explorations program, I combine a short introductory lecture with hands-on experience in my lab. The hands-on experience begins with treating live sperm with caffeine to see its dramatic effect on their motility. Caffeine, which is a drug familiar to most of us, happens to mimic a signal received by sperm in the fallopian tube. The students then run an experiment to see why the caffeine-activated sperm would be better equipped to pass through the vestments of the egg and fertilize it.