New details in O-Kiku's official One Piece biography have squashed the debate surrounding her gender. When O-Kiku was first introduced to the series and got pulled into Luffy and Zoro's early Wano shenanigans, one of the big surprises was that she was actually one of the members of the Akazaya Nine that fought alongside Oden Kozuki 20n years before the events of the arc. Another major surprise was that it was revealed that she was actually born a different gender, but identifies as a woman. While this should have been the end of the conversation, it unfortunately was not in many ways.
Even with One Piece introducing transgender and intersex characters in the series' past, and even the Wano Country arc introducing another character who identifies differently than their perceived gender in the third act with Yamato, O-Kiku's gender has been stirring a strange debate. Now with her official details as revealed through her Vivre Card biography detailing her birthday, favorite food and more (as shared by @newworldartur on Twitter), that debate can be put to bed.
O-Kiku - 1267— Artur - Library of Ohara (@newworldartur) May 1, 2021
Sex/Gender: Male (Female Trans)
Birthday: September 9th (new!)
Age: 22 (new!)
Blood Type: X-F (new!)
Homeland: Wano, Ringo
Favorite Food: Shirataki
Haki: Observation, Armament (new!) pic.twitter.com/Mt7b63UVHE
As @newworldartur also notes about O-Kiku's description, she is described as "male (heart is female)" which they note is referring to an expression that's explicitly used to describe someone who is transgender. This coincides with O-Kiku's response to Luffy and the others early on when they question her gender, and she responds with the fact that she's a "woman at heart."
This really should be the end of the "argument" as O-Kiku's gender is honestly the least intriguing aspect of her character. We've seen her skills as part of the Akazaya Nine, and as the fight at Onigashima has left her in a pretty bloody status the last time we had seen her in action, there are some other major things that fans of the series should be concerned about when it comes to this fighter.
One Piece is releasing new chapters with each new week of Shueisha's Weekly Shonen Jump magazine, and new episodes of its anime each week as well. Both releases are now in the midst of the Wano Country's third act (though the manga is much further ahead), so we'll soon see how this all wraps soon enough!