And I'm wrong; it's Elly whining about being unfulfilled.
Panel 1: We start off with the Queen of Pointless Busywork tell Annie, who's doing some needlework to stave off the suburban ennui that's consumed the shrieking loon she hangs out with, that sometimes she feels so bored with her life.
Panel 2: As we pan out to see Christopher notice the dolly Lizzie is playing with, we see Mrs I-don't-have-enough-time-to-read-the-pap
Panel 3: As Annie reaches for a pair of scissors, she tells Elly that there's always one thing you can do when life seems dull.
Panel 4: The "thing" in question is to have a picky-face Martian princess; as she mentions having to deal with a third child as the sovereign cure for Elly's boredom, we see Lizzie howl as Christopher tries taking her doll away.
Summary: Elly can't deal with the kids she has; bringing a third child into the mix now will just add to her misery and despair. It would be best if she waited a decade or so like she did in the real strip.