Gail Simone, a comic book creator (Birds of Prey!) realized a disturbing trend in how and why female characters were being killed in mainstream comics. So, she compiled a list of characters who died in unnecessarily gruesome ways or somehow became powerless. She proposed that these women were killed off in order to improve the story arc for their male counterparts.
Upon receiveing criticisms from male comic book fans who countered that male characters get killed off as well, Simone replied by stating that there are an overwhelming amount of male characters in any comic universe in comparison to female. Also, often when a male character is killed off, his death is heroic and he “goes down fighting” in comparison to a female character who just turns up dead.
When the character is revived in that typical comic book style of breathing life back into dead characters, he somehow improves either in his power level or general character attributes. An example would be that Batman eventually recovers from having his back broken by Bane, but Bat Girl remains paralyzed after being shot by the Joker.
The website was created in 1999 and unfortunetly hasn’t been upgraded so its format is very simple but certainly worth checking out.