DK used to be bullied when he was a kid/tween.... not to the extent that you hear about these days, or to the extent where he would have harmed himself - but he got picked on for being skinny and dorky. (A few guys would push him around on the playground, etc.)
The bullying is actually the reason he got into martial arts - it gave him the confidence and ability to defend himself. One day, post karate, when the kids were picking on him, he stood up for himself, and ended up fighting and beating the ringleader. They never bothered him again.
DK is already planning to teach our kid(s) karate when they're old enough - he wants them to be able to stand up for themselves or defend themselves as necessary.