What is the current law on compulsory vaccinations in the U.S.? Are there any exceptions for people who don't want to get vaccinated?

Decisions about compulsory vaccinations are made by the governments of each state, and not by the federal government. Vaccine recommendations, requirements, and schedules can differ from state to state. You can find more information at your state government Web site. For most states, you can get to the government Web site by plugging your state's two-letter abbreviation between "www." and ".gov." For example, the official government Web site for New Jersey is www.nj.gov.

Though they may call them "compulsory," most states allow people to opt out of vaccinations by signing an affidavit. However, because you get the majority of your vaccinations before you're 18, the decision about whether you get vaccinated falls to your parents or guardians.

The current controversy over compulsory vaccinations concerns the new Gardasil vaccine that prevents the types of Human Papilloma Virus (HPV) that cause, according to Merck, 70 percent of cervical cancer cases and 90 percent of genital warts cases. Merck (the global pharmaceutical company that developed and manufactures Gardasil) has been lobbying state governments to make the Gardasil vaccine compulsory. The controversy is that HPVs are sexually transmitted, and Gardasil works best when given to girls who are not sexually active — generally when they're 11 or 12. Some people are concerned that giving the vaccine to young girls can encourage teenage sexual activity.

If you're traveling abroad, you may need to get further vaccinations. Those required vaccinations are governed by the country you want to visit, and you can't opt out of them (unless, of course, you decide to cancel the trip). The Centers for Disease Control (CDC) keeps track of which vaccinations world travelers need, as well as keeping updates about health concerns and disease outbreaks around the world.