The next most dangerous thing [after nuclear proliferation] is probably... global warming, and then, right behind that are overpopulation -- we need to get serious about family planning-and trying to alleviate poverty, to get clean, renewable energy, probably with solar panels to the billion and a half people in the world who don't have access to electricity.

The chance for mistakes is about equal to the number of crew squared.

Men should be disqualified for public office. Women should run the planet. They're better than us.

I see what keeps people young: work!

If you think you're a second-class citizen, you are.

If I had to predict, the way things are going, I'd say the chances are about 50-50 that humanity will be extinct or nearly extinct within 50 years. Weapons of mass destruction, disease, I mean this global warming is scaring the living daylights out of me.

Do something. Either lead, follow or get out of the way.