Question to good English grammar experts

Question to good English grammar experts-is it true that the words in the list refer to both a man or a woman:
A fireman,a stewardess,a waiter,a policeman,a fisherman,a chairman. They are from one task on jobs for men and women. But there is no problem to find in the dictionary the words like steward, waitress. Can we call a man- a stewardess or a woman - a waiter or policeman?

When you call for a policeman, or a fireman, (or other profession ending in -man) you are not surprised if a female shows up. These historically male occupations have -man names. In general, the male form can be used for men and mixed sex or unspecified groups, as in, the policemen's union. If you know for a fact that the policeman is female, you will use policewoman. In order to get around the awkwardness, sometimes you can see the sexually neutral policeperson, police officer, or just police (plural) used.

The -ess suffix implies female (waitress, stewardess) and they are simply the female version of the male roots. So a man is never a stewardess, he is a steward. He is never a waitress, he is a waiter. When referred to in a mixed group you almost always are stuck saying "waiters and waitresses" or the ever awkward waitperson or the neutral waitstaff (plural).

Fortunately most professions are able to avoid the issue since there is no sex clue in the name. Pilot, programmer, chef, driver are all general purpose.