AS can occur at any age, depending on the cause. Congenital stenosis is usually seen in patients younger than 30 years old. In patients between the ages of 30 and 70 years, the cause is equally attributed to congenital malformation and rheumatic heart disease. Among children born with AS, 75% are male, and overall approximately 80% with AS are male. Atherosclerosis and degenerative calcification of the aortic valve are the predominant causes for stenosis in people older than 70 years. Ethnicity and race have no known effect on the risk of AS.