A lot of movements use women's involvement to shame men when recruitment is sagging.

Women are secretaries of state and prime ministers - but people still don't expect women to be involved in violence.

The best predictor of a woman's involvement in terrorism, whether it's a secular or religious group, is a relationship with a terrorist: her father, brother, husband or even her son. Terrorism becomes a bit of a family business.

A lot of movements use women's involvement to shame men when recruitment is sagging.

It's cheap, and you have a thinking, breathing bomb that can adjust to circumstances and cross the street to hit another target if the original one doesn't look good.

Misuse of the Koran to provide legitimacy for violence is common, particularly in Europe, where terrorists tend not to be well-educated Muslims.

I did a study of soldiers returning from Iraq, and their levels of PTSD were much higher if they had had to shoot a woman or child, even if they knew the person was a suicide bomber.