If a commercial plant produces abnormal fruit, there is ALWAYS a reason for it. E.g. this part of the plant was too distal given the available assimilate to receive enough <insert nutrition>, which caused the <insert biological process e.g. meiosis in pollen mother cells> to function abnormally, causing the abnormality.

BUT if human is born RETARDED, its muh genes and muh RNG universe.

Why doesn't science study the mothers of retarded children more closely? They probably are the true culprits for virtually all abnormalities in genes/development.