why do carriers of a genetic disease not actually have the disease?

Loise Mausser: A person gets a number of genes from each parent, If one parent has the disease and the other parent doesnt then the child could be a carrier. If one parent is a carrier and the other parent isnt then the child could be a carrier. If one parent has the disease and the other parent is a carrier then the child could get the disease or be a carrier, and if both parents are carriers then the child could get the disease or be a carrier. It just depends on which trait the child gets from each parent....Show more

Thurman Buege: organic decision favors fit organisms. If some affliction is dominant in a inhabitants, quite some human beings would have the affliction and it would impression their high quality of existence and means to reproduce, and thereby bypass on the affliction.