How many gun-related massacres are committed by women? Are gun-related massacres strictly a guy thing? Equal opportunity/gender be dam*ed?

It's part of female nature to act more indirectly. Women like using poison. They also like manipulating men into acting for them.

There are a hell of a lot of men in prison because they let a succubus manipulate them into thinking they wouldn't be real men unless they did what she wanted.

The first school shooting in 1979 was by a female. Brenda "I don't like Mondays" Spencer.

Amy Bishop and Jennifer San Marco shot up their work. 

The San Bernarino terror attack was both the husband and wife. 

But normally a woman goes with poison or using a car as a weapon. Men definitely do more of the mass murders but ironically there are more female serial killers than men.