Masculinity is defined in the play by ambition and power – two qualities that Lady Macbeth possesses in abundance. Shakespeare challenges our preconceived views of masculinity and femininity. Lady Macbeth is a classic femme fatal. She is more ambitious and power hungry than Macbeth.(Jamieson) When She has plotted to kill King Duncan and told her husband he will have to do it he tries to back out of it, so she calls his "manhood" into question. Lady Macbeth is equally as ambitious as her husband, but is unable to take action herself. She tries to get her husband to act on her behalf. Despite Lady Macbeth's desire to be more like a man for the task at hand, she proves to be still the weak female when it comes to the actual deed. (Samuel 2003)
Macbeth informs his wife that "we will proceed no further in this business" She starts to talk about the ultimate definition of manhood, his sexual prowess, when she replies "Art thou afeard to be the same valor as thou art desire?" She immediately questions whether or not he would choose to live a coward. He replies with "I dare do all that may become a man" Feeling he must defend himself against her accusations.