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 dont’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. So I went inside, got a clean one and left the dirty one there