Answer:
Germline mutations
Step-by-step explanation:
Since the egg and sperm cells are referred to as germ cells, then mutations in these types of cell is germline or germinal mutations.
Exogenous (i.e external) factors and endogenous (i.e internal) factors are usually the cause of germline mutations.
Endogenous factors like errors in cell division and generated reactive oxygen species during cellular respiration, often take the higher percentage in the cause of germline mutations.
Exogenous factors which take the lower percentage in the cause of this type of mutation, include direct exposure of the gonads to high ionizing radiations and harmful chemicals. Poor repair of the damaged DNA as the result of these factors often results to varying mutations.