Sounds stupid or silly, I know, but according to an article in the Washington Post, a gentleman living in the DC area was denied health care coverage because he was taking the prescription drug Propecia to fight his male pattern baldness.
The insurance company in question was Kaiser Permanente and they did reverse themselves once contacted by the Post, but it does raise an interesting question about the manner in which health care insurance is run--at least for some companies.
This brought to mind a discussion that I was having about health care coverage in general, though. In 1996, President Clinton signed into law the HIPAA (Health Insurance Portability and Accountability Act), which was stated to help people get and keep their insurance.
The act provides protection such that you are allowed to keep your coverage if you are enrolled (although not necessarily at a reasonable price-- it is up to your individual state to regulate this). Further, it guarantees that you are able to get individual coverage if you have group coverage, move from group coverage to group coverage, or move to group coverage from individual coverage. In the case of the group coverage, this is a good thing because most of these are unrated (don't take into account your pre-existing conditions, etc). In the case of individual coverage, it's a bonus, but there is no guarantee by the federal law that your coverage will be affordable.
What you aren't guaranteed is the ability to move from one individual provider to another. I'm not sure what this guy was trying to do, but I'd guess it was moving from one individual plan to another.