I just went and re-read a few of the older comics with Claire and Clinton after reading todays strip. Suddenly some of their excessive reactions and anxiety can be seen in a new light, and make a lot more sense.
For example, strip
2244. Now we know what sort of things Clinton was really trying to find out rather than go: "YOU wanted to know if she'd done anything creepy? Ha ha! You looked in the mirror lately buddy?" And I can't believe I didn't pick up his first reaction to being asked that was: "Why do you ask?" instead of "Yes."
And now I can see a new totally different reason as to why they were alarmed and upset at being mistaken for twins in strip
2277.
And look at Claire's anxious pose in panel two of
2278. Could what she REALLY have been asking is "He didn't say anything weird about ME, did he?"
Of course, this all assumes Jeph was planning this that far back and didn't just make it up as he went along and went: "Hey, I want to put a trans character in the strip. Lets see...Claire! She'll be perfect!" But after looking at those earlier strips, I'm don't think he did.