DOs (osteopaths) go through med school. DCs (chiropractors) do not.

When I was in school a chiropractic school was trying to seduce us away from PT by telling us that if we went to their school after only 2 years we'd be DOCTORS, instead of all the work we were doing just to be allied health.

I like being allied health, and after 9 years of college and 3 degrees I'm quite aware that there is no way in heck I could learn enough in 2 years to justify calling myself "Doctor."