I grew up in Philadelphia and was a regular guest of many friends who were members of The Union League, Racquet Club, Rittenhouse Club and The Locust Club back in the 70's and 80s. Back then, the Union League was THE power broker club and was "Men Only" until the mid 80's just like the famed New York Athletic Club that back in 1989 broke the sexism barrier and allowed women in.
When I read about "Women Only" co-working spaces in Time I first thought back to how hard women fought to gain entry to Men Only clubs like those. There was an outdated (and by then outdated) reasons why the "Clubs" kept women out at first, but times and women changed. As more women had entered the workforce and were in leadership positions their being denied entry, curtailed them from the opportunities and dealmaking that was going on the "clubs." But the more I thought about it, the more I like the idea of women only clubs even if it walks back on what women wanted in the prior generations. With all the upsetting news about sexual harassment and gender bias in today's society (and it isn't going away), giving a woman a place to feel safe, work without the wandering eye or groping hands of men is really good for them. They need sanctuary, much like the men did in their clubs away from the women. The clubs are about business. Not the search for Mr. or Ms. Right Now.
At the same time, it won't be a surprise to me if we see a rise and return of the men only, so called power clubs, like I grew up having lunches at with friends who were members (I was never a member though was asked a few times to join them,) as there can't be a double standard. That's because clubs and private membership groups can only be one of two things. Inclusive or Exclusive, but not both.