Using Woman or women as an adjective

[mywork.la]

Is it ever strictly correct to use woman or women as an adjective?
For example:

The scientific sample was composed of 100 women directors.
or
The scientific sample was composed of 100 woman directors.
or
should both of these be avoided in favor of the word female.

[RonPurewal]

Wrong folder for this question. Please post it in the General Verbal folder. Thanks.