About 0.1% of the population is at risk of MS. Epidemiological research has however shown that this risk increases to 2-2.5% for people with a first-degree relative who suffers from the disease. If both parents have MS, the risk for the child increases to around 30%. Hereditary factors therefore perhaps play a role in the development mechanism of MS. This cannot however be demonstrated using directly communicable and traceable genetic defects.