The trope that "mom wants another baby and dad flies into a tizzy" is a well-worn staple of sitcoms. In fact, it's so common that I could have sworn The Simpsons had done it in the past. But I guess not. I guess I must have been thinking of the thousands of other "mom wants another baby" episodes.
It even retreads fairly specific territory. Near the end, Homer and Marge decide that their last resort is the sperm bank where Homer secretly made hundreds of deposits over the years. This is also the last resort for Francine in the American Dad "mom wants another baby" episode. It's not the episode you want to invite comparisons to, either, because American Dad really pulled out all the stops. Just thinking about the cartoon mascots at the vasectomy lab makes me giggle.
This episode had some truly funny moments (as when Skinner describes the school as "a hurricane shelter with voting booths," or M. Night Shyamalan's Flop House.) It's just a pity that they were in the service of such a pedestrian plot. The voice talent really proved their chops in this episode, though; Dan Castellaneta's read on Homer's "An ON PURPOSE baby?" absolutely slays me.
