The Pill, the tiny contraceptive which changed the lives of millions of women worldwide, was developed in an obscure laboratory in Mexico City on October 15th, 1951. Invented by US research chemist Prof Carl Djerassi, the mass availability of the contraceptive within nine years led to the liberation of a generation of women.
With its near total success rate, the Pill offered women the chance to take more control of their own fertility and freedom from unwanted pregnancies for the first time. It revolutionised sexual behaviour and changed the nature of modern society. However, as with many a love affair, the Pill's attraction began to wear off and the euphoria of liberation from "mechanical methods" was dampened, as one health scare after another emerged.
By 1974, research was already showing the risks of cardiovascular disease. Other side-effects such as headaches, depression and weight gain were being widely reported. Manufacturers responded to the alerts by lowering the dosage of drugs in the Pill.
The present low-dosage drugs, which combine the two female hormones involved in managing birth control, are the third generation of the Pill. A woman taking an oral contraceptive in the 1990s is likely to be ingesting fewer hormones in a month than her 1960s equivalent might have in a single day. Worldwide, more than 300 million women have used the Pill, including 3 million in Britain. An estimated 100 million currently take it.