Elsewhere in the Middle East, Hayat Boumeddiene, the girlfriend of one of the terrorists who attacked Paris two weeks ago, may be in Syria. French police are still searching for her, and the hunt highlights one of the more overlooked aspects of jihadism: the role of women. About 10 percent of Westerners recruited into the Islamic extremist group ISIS are women. That number is twice as high in France. And they’re taking active roles in planning and executing attacks. What draws them in?