I'm an only child; I never had siblings.
You must have been lonely growing up!  What did you do for companionship?
The proportion of families in the US with only children fell during Post-WW2 baby boom, but I guess I'm a Gen X kid.  Oh, I had imaginary friends!
So before WW2 there were many families with only one child?  That's sad.  Thank goodness for the baby boom!
Oh that was due to the Great Depression.  People couldn't afford to have kids!