I went to buy a dance belt, and my dad made a giant face. and said " are you sure these aren't girl clothes" and had a strong disapproval for it. And my mother made a uncomfortable face.
I'm not sure what to do :S
(by the way i didn't get it, cuz my parents told me to "ask my teacher if i need it" because they felt uncomfortable with it)

Being a teacher, I think you should ask your dance teacher or teachers for help to let your parents know that these are the clothes that you need for class. also you can put a bug in her ear about how pro sports are now using all the same things we wear for class as ways to stay warm on the feild or court. stay true to everything it is a small hurdle to over come.....

If you look around, you can find dance belts without a thong back. www.riversedgedancewear.com . . .

It might be called full-bottom dance belt or dance briefs. But check with your teacher to make sure you're allowed to wear them.

Well you could always tell your parents that it's not that much different from a jockstrap and just lay out the details as to why it looks like "girl clothes". Sometimes the direct approach couldn't hurt.

In today's society, most men do not wear thongs, leotards, and tights. Hearing that list probably brings up thoughts or girls stuff. Are they against those items as well?

Regardless, I would print the following link and show to them, place emphasis on the second and third paragraph.

en.wikipedia.org . . .

If your parents are letting you dance and not use proper equipment, that is like letting you wrestle with out all of the protective gear, or sending you to baseball practice without a glove. From what I understand it is rare, but you can seriously injure yourself without a dance belt.

If they still think this is "girls clothing" and you can find no way of rationalizing this to them here are some options:
1. Ask your teacher what she would do.
2. Go buy it anyway, most are only like 12 bucks.
3. See if you can wear a jock strap, full seat dance brief, I used under armor compression shorts (I don't wear tights) until I got a dance brief. Wear something to get your boys up and out of the way.