For a while, the tactic succeeded pretty well. Women had never been used as suicide bombers in Iraq so when they started to show up in crowds, they killed hundreds of people.

The military has arrested the guy who was training them:

The ringleader was a man trying to recruit women to carry out SVEST (suicide vest) bombings. The cell leader used his wife and another woman, to act as carriers of his next SVEST attack," the military said.

Women have recently been used more frequently by Al Qaeda in Iraq as bombers, with six attacks or attempted attacks this year alone, according to U.S. military statistics. That's out of a total of 19 such attacks since the U.S.-led invasion began in 2003,
 
Rear Adm. Gregory Smith said in a recent briefing. The latest included two women with a history of psychiatric treatment who killed about 100 people at pet markets in Baghdad on Feb. 1. It remains unclear if Al Qaeda has begun using women because it has been unable to recruit new insurgents or because they are more difficult to detect.