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Vaccines prevent between 2.5 and 4 million deaths every year.
Thyroid conditions cause a higher risk of fibromyalgia and chronic fatigue syndrome.
Women are 50% to 75% more likely than men to experience an adverse drug reaction.
The first-known contraceptive was crocodile dung, used in Egypt in 2000 BC. Condoms were also reportedly used, made of animal bladders or intestines.
About 3% of all pregnant women will give birth to twins, which is an increase in rate of nearly 60% since the early 1980s.
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