Here is a brief reflection on the linguistic evolution of the term "guys", and to a lesser extent the word "guy". In my white Chicago upbringing, "guys" was the second person plural that is lacking in standard English (akin to "youse" or "y'all" in other dialects), regardless of gender makeup of the group. I have recently heard people object to the use of "guys" as a standard second person plural, because it is male-normative. I can sympathize with their feelings, but I probably won't change a pretty important feature of the dialect I speak.
Indeed, I have tried to skew in the other direction, reclaiming both "guys" and "guy" as totally gender neutral terms. Again, this is perhaps easier for me given that I grew up and continue to use the singular "guy" to refer even to inanimate objects. So this latest little innovation allows me to bring up my kids in a less gender-hypersensitive way, avoiding referring to the sex of a kid when it's totally irrelevant to what I'm saying.
Anyway, the article I've linked to seems to indicate that I'm not the only one making subtle moves in this direction.