The Distinctive Baritone said: "Martha is usually played by a curvy woman with a "sexy mama" kind of vibe (she refers to herself as "the earth mother" at least once in the play, and has to believably be able to seduce Nick, who can probably have any girl he wants), and when Amy Morton was announced for the Broadway revival of several years ago, I thought she would be completely miscast. However, Morton was great, and seeing her, Kathleen Turner, and Elizabeth Taylor all play the role has shown me that it doesn't really matter what Martha looks like.
Bill Irwin and Tracy Letts gave completely different interpretations of George and both won Tonys for it, so there is definitely room for invention with that role as well. Zachary Quinto will be fine I'm sure, but he is definitely too young for the part, especially opposite a Martha who is over a decade older than he is."
George is supposed to be 46. Quinto is 44. Martha is supposed to be 52. Flockhart is 57.