There is no cure for hemophilia, but treatment has been refined in recent years. In the 1960s, infusion of concentrated clotting factors replaced the whole-blood or plasma transfusions previously necessary, allowing most to administer preventive treatment at home. In the 1980s, however, many hemophiliacs became infected with hepatitis or HIV (the AIDS virus) that was present in contaminated concentrated clotting factor. Blood donors are now screened, and commercial products are now heat-treated to kill the viruses. Genetic testing can identify carriers of hemophilia, and the status of fetuses can be now be ascertained early in pregnancy. Treatments under study include gene therapy by insertion of healthy factor VIII or IX genes and fetal tissue implants.