It seems, however, that if you do want to join then there will be no place for you if you are separated or divorced, according to this article in Forbes. On the Google+ profile page, users are given options for their relationship status but, unlike Facebook, neither "separated" nor "divorced" appear. As the article says, this ignores the fact that 10% of the US poulation is divorced.
Apparently, Google has been criticised before for ignoring the possibility of familial strife - I love the quote from one user who took exception to them inserting "call Dad" reminders into people's GMail accounts on Father's Day:
“I’m sure in a Google-designed childhood everyone would be loved, protected, and nurtured to be the best little software engineer he/she can be. However, I don’t appreciate the reminder of my unpleasant childhood and presumption that I want to speak to my father.”
Perhaps Google could do with a little reality check.