Garry Sykes, male contraceptive trialist, December 2000.
© Science Museum / Science & Society Picture Library
Since 1999, Garry Sykes has taken part in several trials of male hormonal contraceptives based at Manchester University. A pill is taken daily and stops the production of sperm and testosterone, so a testosterone injection is used to replace this as a tablet would either be destroyed by the stomach (if the dosage is too small) or risks damaging the liver (if the dosage is too large). In the course of the trials Sykes experienced side effects of an increased libido and headaches.