What determines the outcome of a mutation?

There are plenty of factors that can induce mutations. There are several harmful rays, such as X-rays and gamma rays, that can affect the DNA structure within gametes and that can cause mutations to occur. There are certain types of food that can also have the same affect. There are also genetic factors that can cause mutations. During Anaphase two where the DNA materials are splitting apart to form gametes, a process known as non-disjunction can occur where one of the gametes has an extra set of chromosome and the other has one or more less set of chromosomes.