In the 1960s several small paperback books appeared, titled "Eggbert", "More Eggbert", Eggbert and Eggberta" and so on. As you can see, they sold for $1. They are now out of print, and sell on E-bay for $20 and up - so if you have any, they are as good as gold! :)
The books were series of cartoon of a boy inside the womb - sometimes alone, sometimes with a twin sister.
The captions are timeless and hilarious.