How it works
A doctor inserts a thin piece of silicon embedded with circuits into the vas deferens. The circuits convert radio signals from the fob to acoustic waves, which cause the material to expand and block sperm.
A second click of the fob contracts the material to unblock the sperm. Removing the device would require just a quick visit to the doctor's office.
Australian scientists have recently completed the design of the circuits. Tests in animals could begin in two years.
Could listening to the radio wreck your fertility? Not quite. Using ultrahigh radio frequencies and signal coding eliminates the chance of accidental activation.