(Live Science) - According to a new study from the University of Chicago, about half of Americans believe at least one of the following medical conspiracy theories.  And one in five people believe at least three of them.  Here they are . . .

1) 37% believe the FDA is preventing us from getting natural cures for cancer and other diseases, because of pressure from drug companies.

2) 20% believe health officials know cell phones cause cancer but aren't stopping it . . . because cell phone companies won't let them.

3) 20% of people believe vaccines cause autism, even though that link has been scientifically disproven.

4)  12% of people believe the distribution of genetically modified foods by Monsanto is part of a secret program called Agenda 21 to shrink the world's population.

5) And 12% of people believe the flouride added to water is a secret way for chemical companies to dump dangerous waste.

The authors say we tend to believe in conspiracies because, quote, "they seem like very compelling explanations for complicated situations."

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