Ah, yes, it's for the pronouns. It's not like it's Google's problem that we say his or her profile -- blame it on the chauvinist English language, with their "mankind" and those professions ending in -man!
I never would have thought that writing gender-neutral language in software would be a harder problem than, say, indexing the entirety of the Internet for perfect search results. Or scalably managing millions of email inboxes. Or allowing for simultaneous document editing. Or making the poptart-rainbow button on the original Nyancat YouTube video.
Has Captain Obvious already visited you on this topic? HARK! SHE ARRIVES!
The Gender field exists purely for advertising purposes. If you don't believe me, visit this page while logged into your Google account. Our all-powerful Internet giant predicts your interests and your gender based on your browsing habits -- hooray!
Here's a screenshot of mine, and, surprise, they predict that I'm male.
Sure, Google has the right to do this, and their nifty free services are worth the cost of their creepy personal-info-gathering-ways in the name of ads, but, of all the criteria you care about, why is gender the most meaningful? I ponder the implications.
Hiding gender from other users on G+ is a red herring. Gender -- like race, heritage, country of origin, sexual preferences, political leanings, income level, you name it -- is nobody's business. At all. Ever.
But wait! There's more!
Someone has gone to the lengths to spotlightingstalking showing female members of Google Plus. It's called Women of G+.
Well, whaddya know! It's a site for women who use Google +, with such useful articles as "How do you know if you're doing it right?", and screenshots of pretty (mostly? all?) white women.
What is this bullllllllllllllllllllshit before me? I'm flabbergasted. Is this supposed to encourage women to join G+? Is this supposed to make female early adopters mo' betta than new joiners? Why is it styled like a tampon site?
I get that "Men of Google+" was the first week of Google+ itself, but it's hard to see this segregated site anything but exploitation.
Google, could you please kill the gender field in G+?