Women are probably the most cutthroat but its not because they are bad people, it's out of a biological necessity. Think about the fact that puberty makes men bigger, stronger, and faster than women. Also think about the fact that a man really bears little risk in having sex with as many women as possible and maybe impregnating them (apart from financially) while such behavior will task a woman physically, emotionally, and also financially. Women are cutthroat because they have the most to lose