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.

With a civilian target, female bombers tend to be more successful and cause more damage.

The issue of motherhood is no longer salient. In fact, the very first female bomber for Hamas posed in her last will and testament video with her two kids.

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.

When I was in Sri Lanka with the [Tamil] Tigers, there were editorials in the paper saying that soldiers really had to stop raping Tamil women at checkpoints because they were just creating more operatives. The [Tigers] were cognizant of this and exploited it: Don't be a victim, join the movement.

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

The terrorists provide an outlet where with just one action, a raped woman can go from being a source of dishonour to her family to being a source of pride in a culture of martyrdom.

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.

When the bombers are women - and children, which I predict we'll see more of - the terrorists get more bang for their buck, because there's more media attention.