We've long known that long-distance bike riding is bad for a man's sex life (heat, pressure, friction = lower sperm count and erectile dysfunction). But women who ride a racing-style bike with handlebars lower than the saddle for more than 10 miles weekly have a serious problem, too—a sustained loss of feeling in their genitals—finds a study at Texas A&M Health Science Center. That sleek, forward-leaning position puts undue pressure on the soft tissues of the perineum and pelvic floor. Riding this way, you may be the hottest, fastest thing on the road but slower to warm up in bed. Better for your sex life: the upright 50's-style ride lovingly known as the "Granny."