How does Shakespeare subvert his characters' perception of gender roles in Macbeth?
Shakespeare subverts his characters' perceptions of gender roles through the pair of Macbeth and Lady Macbeth. The first article linked below presents the case that Lady Macbeth did not in fact liberate herself because, after goading Macbeth into killing, she eventually resorted back to her feminine gentility.
The famous line concerning the overt reference to gender roles is when Lady Macbeth asks spirits to "unsex her" so she can be as strong and stoic as a man to carry out the murderous deeds. The traditional gender roles are that the man is strong and makes meaning through action while the woman is intuitive, emotional and uses words for meaning. This article implies that Lady Macbeth is not liberated because she reverts to her femininity. My problem with this argument is that it implies that liberation means moving from a stereotypical woman to the role of a stereotypical man. Liberation is about moving beyond all roles; so, in a sense she does this, but I really don't think the issue of Lady Macbeth's liberation is relevant to the action.
As this pertains to your question, I think Shakespeare subverts the characters' perception of gender roles by first presenting Macbeth as the strong warrior and then second, by presenting him as subservient to his wife's directions; they take turns being the dominant one in the relationship. Later, Macbeth takes control of the killing spree and Lady Macbeth is guilt-ridden.
So, Shakespeare subverts the reader's perception of gender roles by presenting Lady Macbeth as strong (initially) and Shakespeare subverts the characters' perceptions of gender roles by showing that gender roles are mental or cultural constructs; gender roles cannot be completely reduced to biological makeup. Case in point, Lady Macbeth asks the spirits to physically change her so that she might escape her inherently prescribed gender roles. The subversive move on Shakespeare's part is to show that Lady Macbeth becomes the strong one (albeit as encouraging murder) without changing her physicality (“unsex me” and “make thick my blood”). Although she thought she needed an almost supernatural physical change, she became strong without physically changing; meaning that gender roles are not limited to biology.