Jason Zinoman in The New York Times:
I’m a comedy critic, so being a dad can seem like an occupational hazard. It may be professional suicide to admit, but since having children, I often find myself making lame puns as well as poop jokes. In subway stations, I have been known to silently mouth words to my daughters when a loud train goes by until the noise quiets and I add: “ … and that’s the secret to life.” Look, I’m not proud. The demise of a dad’s sense of humor begins in early parenthood while workshopping jokes in front of babies, tiny philistines who think peekaboo is a hilarious bit of misdirection. It isn’t long before these drooling rubes turn into trash-talking toddlers and fall in love with the scatological. Like so many lazy comics, we parents pander. If jokes work, they stay in the set. Gradually, we become hooked on cheap laughs. Some of us even delude ourselves into thinking we are actually funny.
…The most common dad joke relies on puns. (“What has two butts and kills people? An assassin.”) To redeem them, you needn’t point out that Shakespeare used such jokes.
…Say what you will about a joke like, “What do you call someone with no body and just a nose? Nobody knows,” but it doesn’t age.