User blog comment:Amonymous Korrntributor/Chapter 59 Release Date?/@comment-13234254-20140627101156/@comment-179280-20140627103035

Kodansha said this was [kodanshacomics.tumblr.com/post/79565073216/you-publish-attack-on-titan-right-a-friend-told-me a mistake], and that Nanaba is indeed canonically female.