Down syndrome is an universal phenomemon, affecting all nationalities. Although the greatest risk factor is increased maternal age, the majority of children with Down syndrome are born to mothers under the age of 35, because the vast majority of children as a whole are born to younger mothers. | Down syndrome is an universal phenomemon, affecting all nationalities. Although the greatest risk factor is increased maternal age, the majority of children with Down syndrome are born to mothers under the age of 35, because the vast majority of children as a whole are born to younger mothers. |