Kelly McGillis puts Lady MacBeth on the couch.(Chicago Tribune)

Byline: Michael Kilian

WASHINGTON_So, what's the deal with Lady MacBeth?

Actress Kelly McGillis wonders, Could it have been that she wasn't a mom?

The motives and mental makeup of this most fiendish of Shakespeare's femmes fatales have long fascinated scholars, actors, directors and even theater critics for centuries.

One analyst attributed Lady MacBeth's course of murder, deceit and madness to an overwhelming lust to avenge a kinsman who was killed and deprived of the Scottish throne.

Another simply holds that she is by nature a cold, calculating, ruthless person, and her use of sex, nagging and manipulation to drive her husband to murder his cousin King Duncan is only what you'd expect.

This, of course, does not explain her subsequent grief, guilt, sleepwalking and nightmares, or her obsessive …