The scientific name for the sex organs is "genitalia" or "genitals". They are also commonly called the reproductive organs. The genitals include both organs that can be seen on the outside of the body (the primary genitalia or external genitalia), as well as internal organs (the secondary genitalia or internal genitalia). Sometimes, however, the words "genitalia" or "genitals" are used to refer only to the external sex organs. The sex organs are informally referred to as the private parts or privates.