Doonesbury by Garry Trudeau for December 11, 1973
Transcript:
Girl: Goodness knows I tried to tell her, Jean! "Mommy," I said, "what's with all the babies? You want to be a housewife all your life?" But she keeps turnin' 'em out! Every year, just like clockwork! It's really amazing! I dunno... maybe I'll just have to work on my father instead... as I understand it, he figures heavily in all this... Girl: Oh, yeah?
Any “Irish twins”.