About a week after I took the boys into the pediatrician I finally had a chance to call her office. I called, they had a nurse call back, I told the nurse I actually wanted to speak with the doctor, and she called me back during her lunch.
I'd spent the week since we'd been in being hyper-aware of Gareth when he socialized with others. A couple of the other preschool moms were as well, they told me. :) Watching him so closely confirmed to me that he's a perfectly "normal" five year old. When the doctor called back I asked her what "quirks" she'd seen, since I didn't think I knew what she was talking about. Turns out, nothing. Just that he's super-friendly and some kids like that are overly friendly at times. Who would have thought this was a problem? Ryan and I were both quite introverted all through our primary and secondary school years and always viewed Gareth's extroverted personality as something that would make his school life much easier than ours had been. (We also wonder how on earth he came by it and how we're going to relate to him as a teenager if he remains so social since his experiences could differ drastically from ours.) I told her I'd talked with his preschool teacher and other parents and that they all assured me Gareth is on par with his peers and just fine. And I made sure to let her know that if you use the words "the spectrum", most parents will be worried and freak out at least a bit. She was very apologetic and said she'd misspoken.
Basically I got the idea that she just didn't think through very well what she was trying to say and ended up taking the initial conversation places she hadn't meant to. I was glad she was willing to admit where she'd been wrong and apologize for it. One of the things I've liked about her before is that she doesn't make you feel stupid for asking questions or bringing your kid in. In this case, she didn't seem at all put out that I'd called back to talk more but was very glad I'd done so. I'm not going to throw her under the bus for one bad communication day, so we'll keep going to her for now. If we have more problems in the future, then we'll find someone new.