Germline mutations refer to changes in the genetic sequence of genes in the germinal (egg and sperm) cells. They are passed on from the egg and sperm cells to the offspring during conception.  

Germinal cells, which are found and produced only in gonads, are responsible for sexual reproduction. Germline mutations may occur in a parent’s reproductive cells, either the sperm or egg. These mutations alter the genetic material that the offspring receives from their parents. A child can inherit germline mutations from either parent.