[The contraceptive method that changed the world]

During the past century human life expectancy doubled while the birth rate dropped. The widespread use of effective contraceptives has led to a better control of human fertility and changed the structure of modern societies: the elderly now increasingly outnumber the young. Scientifically controlled human reproduction has also resulted in fewer voluntary abortions. The choice of contraceptive strategies differs by geographic area and seems to be linked to such simple mechanisms as the ''door-to-door'' effect. In European countries where the pill is the most widely used contraceptive, interesting variations in the biological profile of oral contraceptive users can be observed; for example, women taking a hormonal contraceptive have only half the risk of developing ovarian cancer. The world is no longer the same since the advent of the pill.