This, regarding Bai's gender, I've been searching online for a long time and finally found a more reliable explanation. The following is a copy of what I've found there. You can take a look.
The reason why the white woman disguised herself as a man is recorded in detail in the interview of the history of the dark book.
[Regarding Bai's gender: Female]
Everyone must be surprised, and I am the same, but this is the truth."I'm only doing this to let the readers think more deeply.”(Excerpted from the second volume of the interview with the history of Anben Zhai.) In fact, the character setting of Arisu Kazuhiro was largely based on the book "Ronin Kenshin Meiji Swordsman Romance Pond" written by Teacher Tsuki Nobuhiro. Arisu Kazuhiro was another Shishio Reality, while Shiro was a fusion of the breasts of Yumi and Seta Sojiro. Bai's gender was also expressed in a very obscure way by borrowing the writing technique of Kamiya Kaoru's fake death. There were two reasons why everyone thought Bai was a male: (1) Bai said it himself. (2) He always wears men's clothes when fighting. Now, I'll answer this question for everyone.
As for Bai's background, everyone knew that Bai had been wandering around since she was very young. Due to the incident with her parents, she sealed her ability and decided not to use it anymore. Even though he was almost raped once, he didn't use it. However, she began to vaguely understand the inconvenience of being a girl, so she began to wear men's clothes. (This scene was deemed unsuitable for Shōnen manga, especially for Naruto's style, so it was later cut.)）Later on, when he met Amagazu, this belief was even more firm (To Amagazu, a strong ninja was more useful than a beautiful woman, just like how to Shishio, Seta Sojiro was more useful than Chest Yumi). However, a girl's natural love for beauty could not be changed. That was why she dyed her nails, kept her long black hair, and wore women's clothes when no one was looking. As for why he told Naruto that he was a man, I think anyone who knows Bai Shanliang's personality should understand. Besides,"he had actually left a lot of clues for the readers.”(Excerpted from the second volume of the interview with the history of Anben Zhai.) If you are interested, you can look for her (For example, she doesn't have an Adam's apple.)）
The above contents are respectively taken from Naruto Information Setting Collection, Naruto Character Record White Chapter, Naruto Advent Book, Anben Zhai History Interviews Volume II, Anben Zhai History Interviews Volume V, and are hereby declared.
We can't just analyze it from the surface, but we have to understand the evidence from the essence. Most of the people who said she was a man have never seen the second volume of the interview with the history of Anben Zhai.
This book comes from：m.funovel.com。