"I use the behavior patterns of serial killers to make my point in this regard, which some dismiss as 'too extreme', but for the underlying tendencies of each sex to be effectively contrasted, one needs to examine the extremes, to look at where each sex goes when truly pushed.
The first pattern is the Raw Numbers. Male serial killers outnumber their female counterparts by a good ten to one and kill in greater numbers, as well.
The second pattern is the Methodology. Males tend to 'violate and butcher'; stabbing, shooting, rape, mutilation [which is often sexual in nature], dismemberment, 'trophy taking' [again often of a sexual nature], cannibalism and necrophilia. Females tend to poison and pass the death off as accidental or simply hide the corpse.
The third pattern is Motivation and this is the key to the above. Males tend to kill for power over their victims, who are overwhelmingly female and frequently prostitutes, easy targets, 'invisible and disposable', which also makes them 'morally deserving' of their fate from many a killer's point of view.
Females almost always kill for financial gain – the classic Black Widow who kills for insurance - or for 'self esteem' – the hospital Angel of Death who kills to 'end suffering'. Yes, these are also about gaining power, but killing tends to be a route to such, not the destination itself.
Even the great Exception That Proves The Rule, Aileen Wuornos, kept killing for money. Her first kill was survival, the beautiful irony that she likely killed a serial killer who had targeted her. And her rage at her own life long sexual abuse drove her on. But to me that just facilitated her emotions. She used the money from her victims to provide for her girlfriend, so you could say she killed for love.
Now there are men who do the same thing, but they also tend do it in the same way. They kill the victims of their robberies to keep from getting captured and tend to do so 'plain and simple', with none of the intimate ritual of the sexual serial killer.
Women will kill to protect their children and their homes and will do so with great savagery. But as a rule, they don't kill merely to feel powerful. That is almost exclusively The Male's domain."