Modern contraceptive technology is more than a technical advance: it has brought about a true social revolution, the 'first reproductive revolution' in the history of mankind. This latter was followed in rapid succession by other major changes in human reproductive strategies. In the human species, sexual activity began to lose its exclusive reproductive meaning at an early stage of its evolution. Human beings must have practiced non-conceptive sex from the outset and therefore must have had a need to avoid, rather than to seek conception during intercourse from time immemorial. The search for methods to control fertility went on for millennia, but a valid solution was only found during the twentieth century, when the population explosion h...