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 do remember, don't you?
When we were leaving the hospital, you noticed that our baby had pooped.
Then you said:
Please go change the baby, I’ll wait for you here.
So I went inside, got a clean one and left the dirty one there.