|After 10 years, the wife starts to think their kid looks kinda strange so she decides to do a DNA test.|
She finds out that the kid is actually from completely different parents.
Wife: Honey, I have something very serious to tell you.
Husband: What's up?
Wife: According to DNA test results, this is not our kid.
Husband: Well you don't remember, do you?? When we were leaving the hospital, we noticed that our baby had pooped. Then you said, 'Please go change the baby, I'll wait for you here.'
Wife: Yes, I do remember.
So I went inside, got a clean one and left the dirty one there...