Genetically engineered pigs would produce the human blood-clotting protein factor 8 in their milk. Administration of the protein is very important to haemophilia patients. Haemophilia is an inherited disease marked by defective clotting of blood. Such patients tend to bleed heavily following an injury. Bill Drohan and his colleagues at the laboratories of the American Red Cross in Rockville, Maryland, say the protein would be free from human viruses. Many haemophilia patients have been infected with viruses such as the HIV and hepatitis virus after receiving factor 8 from contaminated human blood in 1980s. But, the factor 8 from pigs would be safe and can be produced cheaply and easily ( New Scientist , Vol 155, No 2101).