When I was two years old, I asked my mother the immortal question:

"Mom, how do women become pregnant?"
"Well, Nathan, when a man and a woman have a special kind of love, that love turns into a baby and grows inside the woman until it's ready to be born."

A few minutes later, I started crying. My mother got very concerned, and asked me what was wrong.
"You and Daddy don't love each other anymore!"
"No, your daddy and I love one another very much. What makes you think we don't love each other?"
"Well, you loved each other to make me, but if you still loved each other, I'd have a little brother or sister, wouldn't I?"

At this point, my mother went into more detail.