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The average human gut is home to perhaps 500 to 1,000 different species of bacteria.
The first-known contraceptive was crocodile dung, used in Egypt in 2000 BC. Condoms were also reportedly used, made of animal bladders or intestines.
Cytomegalovirus affects nearly the same amount of newborns every year as Down syndrome.
Asthma cases in Americans are about 75% higher today than they were in 1980.
About 100 new prescription or over-the-counter drugs come into the U.S. market every year.
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