Which organ is NOT part of the reproductive system in females?

The testes are not part of the female reproductive system, as they are the male reproductive organs responsible for producing sperm and hormones like testosterone. In the context of the female reproductive system, organs such as ovaries, the uterus, and mammary glands play critical roles.

Ovaries are essential for producing eggs (ova) and hormones such as estrogen and progesterone. The uterus serves as the site for implantation and fetal development during pregnancy. Mammary glands are involved in the production of milk for nursing infants. Therefore, the testes stand out as the organ unrelated to the female reproductive anatomy and functions, establishing them as the correct answer to the question.