Answer: A mutation in his offspring.
Explanation:
Gametes are sex cells produced by an organism. They can be eggs or sperm. A man produces sperm, which are haploid cells (half of the genetic material). They fertilize an egg during reproduction, which also has half of the genetic material. Between the two, they complete the necessary number of chromosomes that the formed zygote will possess.
If there is a mutation in one of these gametes, it will not affect man because they are not somatic cells that are part of his body with essential functions. This gamete with a mutation can fertilize an egg, then the mutation will be found in the zygote. This means, the mutation in a man´s gametes would affect his offspring.
