Got a child. Little under a year old.
We go to a little baby group nearby. We visit it from time to time. Just like 6 different babies there.

One baby has brown eyes. Mommy and daddy have blue eyes. Oh...

Next baby is blonde. Mommy is blonde. Daddy is blonde. Someone commented, that blonde was very likely with mommy and daddy. She said, no, her mother-in-law is black haired. She proves it by saying, her oldest son has black hair.... Oh....

Out of 6 parents pairs, we had 2 cheating. 1/3. And for the other 4, well, we only ever met the mother and they have not told us anything about their husbands.

This leads me to only one conclusion: People are terrible in high school level genetics. I know, it is not 100% correct, there are special cases and exceptions. But it it 99% correct.

To quote Rex Harrison: "This is what the British population calls an elementary education."