FiReaNGeL writes "Researchers successfully corrected hemophilia, the oldest known hereditary bleeding disorder, in dogs and mice. They introduced the gene coding for clotting factor VIII, which is defective in type A hemophilia, in the liver of newborn animals. All animals achieved expression of the clotting factor, averaging 139 and 115 percent of normal factor VIII activity and are stable after more than a year. The treatment targeted newborns exclusively for two reasons; their liver is still developing and their immune system is immature, facilitating the gene transfer. Researchers plan to perform tests in higher primates in the next few years. A summary of the research and the reference to the original paper are available."