Kimbrough, Robert. "Macbeth: The Prisoner of Gender."
Shakespeare Studies. 16 (1983): 175-190.

Thesis: At the end of his first section Kimbrough states his thesis very clearly:

[T]he drama of Macbeth contains a fierce war between gender concepts of manhood and womanhood played out upon the plain of humanity. In a metaphoric sense, as well as in the final dramatic siege, Macbeth loses the battle. Macbeth's death, first psychic then physical, stems from his failure to allow the tender aspects of his character to check those tough characteristics which are celebrated by the chauvinistic war ethic of his culture, championed by his wife, and defined in the extreme by the nature of the first two murderers. In his attempt to "better" himself, he is "helped" by Lady Macbeth, whose tragic career parallels and counterpoints his. Although they fail miserably on the stage of this life, Shakespeare constantly keeps before us their potential for human fulfillment. In spite of their isolating, alienating behavior in the play, a bond with the audience is maintained so that we are not merely repulsed; we are moved through pity to understand and to fear the personal and social destructiveness of polarized masculinity and femininity.  (176-177)
Kimbrough then proceeds to support this statement, point-by-point. First he shows how the culture of Shakespeare's time valued masculine toughness over feminine tenderness. Then he explains how Shakespeare emphasizes the contrast between the Macbeths' murderous masculinity and an ideal of the natural as "good, balanced, positive, normal, generative, and healing" (178). Finally, Kimbrough traces Macbeth's descent into despair and Lady Macbeth's descent into madness while showing how each of them retains our sympathy by their awareness, however dim, of the worth of the natural feelings which they have tried to kill within themselves.

Bottom Line: Kimbrough's heart and mind are both in the right place.