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Astigmatism is the most common vision problem. It may accompany nearsightedness or farsightedness. It is usually caused by an irregularly shaped cornea, but sometimes it is the result of an irregularly shaped lens. Either type can be corrected by eyeglasses, contact lenses, or refractive surgery.
Although puberty usually occurs in the early teenage years, the world's youngest parents were two Chinese children who had their first baby when they were 8 and 9 years of age.
The first oncogene was discovered in 1970 and was termed SRC (pronounced "SARK").
In the United States, there is a birth every 8 seconds, according to the U.S. Census Bureau's Population Clock.
After a vasectomy, it takes about 12 ejaculations to clear out sperm that were already beyond the blocked area.