One woman and a number of men is not a recipe for stability!

You need a test-pilot in case something unexpected causes an emergency in flight. The Apollo test-pilot astronauts all had either master's or doctorates in engineering, so the pilot would probably have that as their secondary ability. They'd probably also be in command (as most test-pilots are military, that seems a good position for them).

The NASA reference mission supposes a six-man crew. So the six specialist areas would probably be:

Pilot/Commander
Mechanic (upkeep and repair of the main systems)
Technician (use of scientific equipment, maintaining communications etc)
Doctor (and medical science)
Geologist
Other science (meterology, life-detection and characterisation)

Each astronaut, as well as their main role would also be back-up for someone else.