The wisdom of others

A significant other
was my mother,
and she had two other.
"You don't want to be an astronaut",
she said,
"for the ground, she is hard,
and when you come back,
you will bang your head",
she said.
I was a child of some delicacy
and knew she had the wisdom
of prophecy.
And not to be outdone,
though some years later,
"What is two plus two?" axed
my dad.
"I don't know", I said.
"It's too many in
one single bed."