Is there any chance you could be retarded?

So I went last night to Bouffant to have Sarah get my rapidly growing hair back under control. She gave me a great and much needed cut and I got up from her chair feeling like a new woman. Until I went to check out. One of the two women at the counter was being very sweet, asking if I knew the gender, name, etc, of the baby-to-be. The other women upon hearing that the due date is 2 months away, asks, "is there any chance it could be twins?" I just looked at her with my best look of death and disbelief and let out a big "ughh" type sigh of disgust. This is the first idiot comment I have had with this pregnancy and I was totally unprepared. Obviously people have no idea what they are really saying and to whom. What she meant was that she was not used to what a 32 week belly should look like. What she ended up saying esentially was, wow, you look really huge. Saying this to a woman, nonetheless, a very pregnant woman, is about the most annoying comment you could ever make. She followed up with "well, I'm a twin myself" as if that made me not want to hit her in the face any less. Too little too late as she could tell I was not amused. So I drove home trying to think of the best possible comeback for these types of comments. I want something that shows I am not amused, but doesn't come off as too terribly rude. Any ideas?