Insurgent groups also face pressure when it comes to recruiting members, causing the group to expand their bases to sustain the group's position. It has been argued that the introduction of women and girls into combat “generally came about in response to logistical demands: the mounting number of casualties, the intensified crackdowns by government, and the ability to escape detection more easily than men.” An example of this was in January 2002 when the spiritual leader of Hamas renounced the use of female bombers. Later on in the same year, Hamas wasn't enthusiastic about adding women into their ranks. Then in January 2004, Hamas used their first female suicide bomber. Hamas defense to this was evolution of their fight. Citing easier access to reach targets, Hamas stated that women are the reserve army. When there is a need they will use them. On average, it is calculated that terrorist groups that use suicide bombing as a tactic wait around 13.5 years before employing women. However, women are reported to have higher kill rates than men, on average killing four times as many people as men do.