I was going to answer the title question, "Both."
But since JLahrman [whoever he is] brought up the question of what would we think of a women's only golf club, I must say, why the heck not? And therefore, by logical extension, why not a men's only club?
It would make sense to have both such animals on architectural grounds alone. You wouldn't have to muck up the men's course trying to figure out how to make it playable from the forward tees ... you just wouldn't have any. And by the same token, you could build a better course for women if you built it to their scale, and didn't have to worry about stretching it to 7200 yards.
I do understand the gender discrimination issues. Neither my wife nor my former female associate thought it was cool that I have consulted for years at an all-men's club [Garden City]. And I do have daughters. And I've known lots of very good women golfers who could get around any course (including Pine Valley) at least as well as me, and I don't see why they should be FORBIDDEN from playing those few men's clubs ... if I built a course, anyone would be welcome to try and play it.
But I don't think I should set the rules for everyone else.