Screening means "testing for diseases which existence is not known beforehand". We divide our screening policy into genetic screening and screening for sexual transmitted diseases (STD's) (viruses and bacteria). Screening for STD's does not really involve ethical problems, however, genetic screening does. Genetic screening - if it is unconditional screening - will very easily lead us into positive eugenic. Conditional genetic screening of donors are done in case the recipient is a know carrier for a specific genetic disease and where the child will have a risk to inherent the disease if the donor is a carrier of the same genetic disease. Such tests are called conditional screening.