Joshua Lederberg and Edward Tatum announce their discovery of bacterial conjugation, meaning that in effect bacteria mate and transfer genes

The Medical Research Council in Britain produces a report, by Austin Hill and Richard Doll, linking smoking and lung cancer

George Gey uses cancer cells from Henrietta Lacks to propagate the first human immortal cell line to succeed in vitro, cells which survive still in laboratories all over the world

US microbiologist Jonas Salk announces the discovery of an effective vaccine against polio

The birth control pill wins FDA approval in the US and goes on sale

The drug Thalidomide, synthesized in West Germany, is shown to have been the cause of severe defects in about 12,000 children born in 46 countries

British surgeon John Charnley pioneers the technique of joint replacement, giving a patient a new hip in a small hospital in Wrightington

Surgeons Michael Bakey in the USA and Vasilii Kolesov in the USSR pioneer coronary bypass surgery, using the patient's mammary artery

South African surgeon Christiaan Barnard, in Cape Town, transplants the heart of a young woman into a 55-year-old grocer, Louis Washkansky

British scientists Patrick Steptoe and Robert Edwards fertilize in a test-tube eggs removed from human ovaries

The Tuskegee syphilis experiment in Alabama becomes a major scandal after a whistle-blower reveals the details

Louise Brown, born in England, is the first test-tube baby, having been conceived by IVF (In vitro fertilization)

The Global Commission for the Eradication of Smallpox announces that the world is free of the disease

AIDS (Acquired Immune Deficiency Syndrome) is described for the first time in a US medical journal

The drug AZT (azidothymidine) offers hope as a way of inhibiting the progression from HIV to AIDS

The drug Viagra wins government approval in the USA as a treatment for male impotence

At the turn of the century, it is calculated that 36 million people worldwide are infected with the HIV virus

Leland Hartwel, Paul Nurse and Tim Hunt win the Nobel Prize for their discoveries of key regulators of the cell cycle

A deadly new form of pneumonia, SARS (Severe Acute Respiratory Syndrome) is first reported in Hanoi and soon spreads globally

Two years after its first appearance, the World Health Organization announces that the deadly disease SARS has been 'eradicated'

French surgeon Bernard Devauchelle and his team in Amiens carry out the first human face transplant

The Ebola virus epidemic begins, infecting at least 28,616 people and killing at least 11,310

Cuba becomes the first country in the world to eradicate mother-to-child transmission of HIV and syphilis

COVID-19 pandemic: First known human case of Coronavirus disease 2019 is in Wuhan, Hubei, China