Biotechnology and genetic engineering involve manipulating organisms or their genes. Key techniques include classical biotechnology methods like selection and hybridization, as well as molecular biotechnology techniques like gene transfer and recombinant DNA technology. Some applications of biotechnology include producing therapeutic proteins by inserting genes into bacteria, DNA fingerprinting to identify individuals, and gene therapy to treat genetic disorders. However, genetic engineering is also controversial due to potential dangers and its opposition in some parts of the world.