Why female shooters are rare

(CNN)Two suspects believed to be students used handguns and opened fire in two classrooms at the STEM School Highlands Ranch near Denver on Tuesday afternoon, authorities said. One was an 18-year-old male, the other a female juvenile, according to Douglas County Sheriff Tony Spurlock. The FBI defines an active shooter incident as “an individual engaging in killing or attempting to kill people in a confined and populated area.” Sign up here to get The Results Are In with Dr. Sanjay Gupta every Tuesday from the CNN Health team. On January 30, 2006, Jennifer San Marco visited her former place of employment, a postal distribution center in Goleta, California, and fatally shot six employees after killing a one-time neighbor. She then …