Helen Caldicott Speaks Out Against Nuclear Arms.

The Australian-born activist helped found and was the first president of the Physicians for Social Responsibility (PSR) and the Women's Action for Nuclear Disarmament (WAND). Her new autobiography "A Desperate Passion" is about her life, activism, and the effect of notoriety on her personal life. In 1985 PSR's umbrella affiliate, the International Physicians for the Prevention of Nuclear War, received the Nobel Peace Prize.

Helen Caldicott is a pediatrician and the president of Physicians for Social Responsibility. The Australian is a leading figure in the fight against nuclear war and the nuclear arms race. She views nuclear arms as a health issue, and has left her job as a pediatrician to devote her time to advocating for nuclear disarmament. She has recently formed the Women's Party for Survival and is planning a march on Mother's Day.

Pakistan has an estimated 80 to 100 nuclear warheads. How secure are they? Veteran investigative journalist Seymour Hersh talks with host Terry Gross about Pakistan's nuclear arsenal and what Pakistan and the U.S. are doing to keep it safe.