Actually, 34.5 million people have chronic jaw pain, so the market isn’t as small as you think.
I didn’t mean to imply that I would only consider an agent who has his/her own problems with jaw pain. That would be silly.
Just as a person would probably look for a like-minded agent for other topics, I would prefer someone who has some personal or indirect experience with the issues my book discusses.
If I were writing a book about polo, I would love to find someone who either loved watching polo or had played at some point. If I were writing a book about nature, I would prefer a hiker or birder, someone who appreciated nature.
I am certainly open to working with any good agent who could get excited about my book. I have had some nibbles, and as far as I know, those agents don’t have any jaw pain issues.