At the end of the 20th century was a era of the Internet, the beginning of the 21st is said to be the age of biotechnology. The potential economic and social impacts are staggering. But what is it? Modern agricultural biotechnology refers to various scientific techniques, most notably genetic engineering, used to modify plants, animals, or micro-organisms by introducing in their genetic makeup genes for specific desired traits, including genes from unrelated species. For centuries people have crossbred related plant or animal species to develop useful new varieties or hybrids with desirable traits, such as better taste or increased productivity. The United States has more than a decade of experience in regulating bio-engineered foods. About 50 varieties of bio-engineered food crops have gone through the US government regulatory procedures, and thousands of foods containing ingredients from these bio-engineered crops are currently on the US market. Biotechnology also contributes to such diverse areas waste disposal, mining, and medicine.