@Spudley -- Re: There is no place for discrimination on Facebook
You may advertise for a builder in a DIY magazine, knowing full well that most of the people reading it are going to be men.
If that is indeed the case, then that is discriminatory. One would better advertise (not "invite") in a DIY magazine, knowing full well that most of the people reading it are skilled in construction, mechanical engineering, are part of the "maker" community, etc.
I know several women who know their way around CAD programs and CNC machines, and might just read such magazines.