Promoting that your book (or movie or album or whatever) is created by a woman is like promoting you have a singing dog. The attraction is not that the dog sings well, but that it sings at all. Attaching the gender of the creator to the reasons why your audience should care about your creation is putting your work in the category of a sideshow freak. It’s something people gawk at, take pitty on, and applaud but never take seriously because it couldn’t stand on it’s own.
The gender of the creator does not tell the audience that the creation is good. Being male or female or whatever does not convey talent. People don’t buy Harry Potter because it’s written by a woman. People buy Harry Potter because it’s a good story.
In 2016 the only reason to put a gender to your book is because it wouldn’t sell in the fair and open market without it. You are appealing to your audience’s need to seem “open minded”. Most of these people aren’t going to actually read your book. They are buying it so they can feel better about themselves, give it a place of honor on their bookshelf and show off to other people how “progressive” they are. They are giving the singing dog it’s nickle for performing.
If women really and truly want to be seen as equals in the writing (or any) profession they need to drop the gender shtick and not be afraid to let their work stand on it’s own merit. To be judged just like everybody else. To stop hiding behind the shield of sexism and risk learning that they just aren’t good enough yet so they can strive to improve themselves and their work in the future. Without this risk they are just singing dogs. Nobody expects the singing dog to sing well. They just applaud that it exists and then forget about it when the next novelty comes along.