To me this mangaka thing feels realistic at the same time I wonder: "70% of your country doesn't have running water or plumbing or electricity. This seems like a strange time to bring up manga. I would rather have e book about: "How yo survive?", "What can you eat?" Etc.
The second thing that people seem to be talking about is Kiruko liking Maru. In a world where Brian transplants are just possible, people wonder if he is "gay", "trans", etc.
To me Kiruko seems like she is beyond trans, to be trans and became a full girl with body, a period, etc.
About the brain: well the brain receives a lot of information from the body and releases a lot of chemicals and hormones too.
I think that Kiruko has been living for for years now in a female body while trying to keep a male identity. In essence Kiruko became a tomboy girl. Which is probably why Maru likes her so much.
So in some ways I agree with people that said that Kiruko is more likely became a bisexual. Haruka might have been bisexual or straight but after living. Half his childhood in a Boy's body and the following 5 years or so in a female body then it is likely that the lines are no longer straightforward.
I don't think that Robin's forced sexual encounter pushed the scales any place. Kiruko was just confused and suffered a mental breakdown and an identity crisis.
Kiruko has not yet come go terms with her new identity and it's starting to surface. Sooner or later she is going to have to talk with someone who is going to help her accept who she is now.