The mutation must occur in a germ cell for it to be passed from a woman to her offspring.

Here's why:

* Germ cells are the reproductive cells (sperm and egg) that are responsible for creating the next generation.

* Somatic cells are all the other cells in the body (skin, muscle, etc.). Mutations in somatic cells affect only that individual and are not passed on to their children.

Therefore, a mutation in a germ cell (egg) will be present in every cell of the offspring, including their germ cells, making it possible for the mutation to be passed on to future generations.