Character Analysis
Gretchen Potter is a PTS club member, the first in the group to start her period, and also the only Jewish girl in the club (thereby representing the JCC side of the YMCA versus JCC joining debate). We don't know a whole lot more about Gretchen, though we do know that Nancy has no problem shaming her. Check it out:
When Gretchen helped herself to six Oreos at once Nancy asked her how much weight she'd gained over the summer. Gretchen put back four cookies and said, "Not much." (5.1)
Ouch, right? This is such a painful interaction, and Gretchen clearly lacks the self-esteem to feel good about herself in the face of Nancy's subtle jabs. Good thing Gretchen gets her period first, then, and shows Nancy up for once.