Mutations occurring in which type of cell are not transmitted to offspring?

Mutations that occur in somatic cells are not transmitted to offspring because somatic cells make up the tissues of the body and do not participate in reproduction. These cells undergo mitosis for growth, repair, and maintenance of the organism, but any mutations that arise in these cells remain confined to that individual and cannot be passed on to the next generation.

In contrast, germ line cells (which include sperm and egg cells) are responsible for passing genetic information to offspring; thus, mutations in these cells can be inherited. Likewise, reproductive cells specifically refer to the gametes that will combine during fertilization, and mutations in these cells will also affect the next generation. Stem cells, depending on their type (such as embryonic or adult stem cells), can also give rise to germ line cells or other cell types but are not specifically tied to the inheritance of mutations unless they give rise to reproductive cells.

Therefore, the correct answer highlights that only somatic cell mutations are limited to the individual and do not enter the genetic lineage of offspring.