It reminds me of the bumper sticker I saw on a similar Moomobile: "You don't know what a full-time job is...until you're a parent!"
At first I was felt insulted, etc. But then I thought about it and decided differently.
I figure that I'm getting by on part-time work, by that breeder logic. Part time feels pretty right to me, in that case! And every time I leave work and go back to my child-free home and enjoy the peace and quiet, I am glad I will never know what "full-time work" feels like.
They don't know the half of it, do they?