Just killed a new advertisement "Growths", where a father playfully asks his son:

How old are we?
Thirty five! I am five, and you, Dad, thirty.
......
My mom is twenty!
Tess, that is a secret.

Of course, the secret is, if the mother is twenty and the son five, it means that the 24-year-old father stumbled on the future mother when she was 14.