I think that at the time, it was just a dig at Marcy Darcy's character....that she looked boyish or androgynous.
Maybe it was a joke about her plastic surgery and changing appearance.

Anybody who is a fan of people snapping on each other..a la Fred Sanford and Aunt Esther from Sanford and Son, Al Bundy and Marcy used to really get in some good jokes.

I was a big fan of this show and the woman who played Marcy was one of the first stars that I remember coming out. Show was funnier back when her original husband, Coach K from Duke, was on there.