Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Gender verification in sports (also known as sex verification, or loosely as gender determination or a sex test) is the issue of verifying the eligibility of an athlete to compete in a sporting event that is limited to a single sex. The issue arose a number of times in the Olympic games where it was alleged that male athletes attempted to compete as women in order to win, or that an intersexed person competed as a woman. Sex testing began at the 1966 European Athletics Championships in response to suspicion that several of the best women athletes from the Soviet Union and Eastern Europe were actually men. At the Olympics, testing was introduced at the 1968 Olympic Winter Games in Grenoble. While it arose primarily from the Olympic Games, gender verification affects any sporting event. However, it most often becomes an issue in elite international competition.