Among the most common recessive genetic diseases is cystic fibrosis (or mucoviscidosis): one in 25 people on average carries a mutation on the CFTR gene (more than a thousand different mutations on this gene are known of); the disease occurs in 1 in 2,500 individuals. Male infertility may be a symptom of the presence of a mutation on the gene responsible for the disease. The test examines the 50 most common mutations in Central Europe, covering more than 90% of reported cases. If a partner is found to be carrying a mutation, Next Fertility ProCrea will, on request, perform a second level test on the partner in order to more accurately assess the risk of conceiving a sick child.