Biological computers use living cells instead of electronics for processing data. They use chemical inputs and molecules like DNA and proteins. While still basic, researchers have programmed cells to complete logic gates. Biological computers could be mass-produced cheaply and may be more reliable than electronic computers. Challenges include that cells may react unpredictably and biological computing combines biology and computer science in new ways. Today, some companies are using techniques like CRISPR to program cells for tasks like disease detection and treatment.