In the previous answer ῾σερβιτὀρα῾ was translated 'server'. Now in this answer 'server' is marked as a wrong translation. Duo needs a bit of editing here!
Normally in english the second 'the' would not be used; it is implied by the 1st. That is accepted in the grandfather and grandmother example but not in this case.
While we understand the necessity to not distinguish between male and female in job descriptions the expressions: "male waiter and female waiter" are not the actual translations.
What we have opted to do and which appear in our incubator is to include the titles as in this sentence: "Η κόρη μου είναι μία σερβιτόρα" for which we have translations..."My daughter is a [waiter/server/waitress]. Genderless job titles are not yet universally accepted and while we are promoting it as a language teaching course we need to take into account what the general learner may be aware of. Thank you for your contribution.