One day, a father and his son were walking in the woods on their way home when suddenly they came upon two dogs mating in the brush.
"What are they doing, Dad?" asked the small child, staring intently at the scene before them.
"They, um, they're making a puppy" said the boy's father, as he grabbed his coat and moved him along quickly. A few nights later, the little boy woke up and got up from his bed to go to the bathroom.
As he walked by his parents' room, he heard strange noises coming from within. He opened the door and was surprised to see his father on top of his mother, moving in a strange way. His father looked up and saw his son - instantly, both mother and father froze. As the boy's mother grabbed for the sheets to cover herself up, the father got up and hustled his son out of the bedroom.
"What were you doing to Mom, Dad?" asked the little boy, who still wasn't sure what he saw. "Your mother and I were, well, we were, ah, trying to make a baby - you know, maybe a brother or sister for you" said the boy's father, now confident that this would satisfy his son's curiosity.
"Oh" said the little boy, thinking hard for a minute. "Y'know Dad, when you go back to bed with mom, turn her over, please - I'd rather have a puppy".
Stolen from: Hale McKay of It Occurred to Me