Are people with parents/family who are teachers always good at the subjects they teach?

[CamilaP]

I don't know whether or not that's true for everyone. My mom is an English teacher here and she's been teaching it to me since I was little. I think I'm pretty good at it. By far my favorite subject and the one that I'm best at.

[Anonymous]

Definitely not me my parents are both teachers in the same subject and I was still terrible.