"One of the major things we use gender information for on Google+ is for picking gender pronouns - her, his, theirs - when we refer to you. Google is committed to building products that people all over the world use, and in some languages gender is much more deeply part of how sentences are formed than in say, English. Having gender information helps to make Google+ more conversational. If you decide to make your gender private on Google+, we'll to use gender-neutral language to describe you whenever someone else encounters gender-related information about you but doesn't have permission to see your gender. For example, instead of saying 'Greg added you to his circles' or 'Frances added you to her circles', we'll say 'Greg added you to their circles' or 'Frances added you to their circles'. Yes, I know this is grammatically questionable. You don't need to message me about it. We value helping people control their privacy as being much more important than being grammatically perfectly."