The second question is more difficult and depends on the definition of congenital. If a baby is born with a defect that has occurred in the baby's ancestors at a rate higher than in the normal population, it is likely to be genetic and inheritable. But it also could be caused by toxins in the environment, such conditions possibly being available to the baby's ancestors as well. Some diseases appear to be congenital, but are actually caused by infectious organisms. Biliary atresia in children had been considered a congenital, genetic defect for many decades. Then it was discovered that these fetuses had been infected by a virus that caused the problem. Other congenital diseases may not be recognized as such because they don't reveal themselves for many years after birth. Lyme disease in young children was considered to be a genetic disease until a persistent mother bugged Yale Medical Center until they discovered the organism.