Terri or Terry?

Tomorrow, we find out whether Henry will be the older brother to a baby boy or girl.

When we ask him if he wants a baby brother or sister, he always says he wants whatever we say last.

For example:
"Henry, do you want a baby brother or sister?"
"Baby sister"

"Henry, do you want a baby sister or brother"
"Baby brother"

He's probably thinking what we're thinking; we'd love to have either.