wow__ So Haruka really his little brother, then it was incest??
Actually the answer to your question is yes. He did not look 'relieved' to see the result but rather tense. Tatsuya already said that he wont let Haru go even if the are related or not. Thus, the chapter 'Secret' is about Tatsuya letting Haru believe they are just step brother instead of half brother. The father might have an illicit relationship with the mother even before tatsuya's mother died. So yes, this is incest.
Yeah.It's sad. I hope it doesnt weigh too heavy on Tatsuya.. :/
yrs he is his brother
he was the half-brother, referring to this page>>> http://www.mangago.zone/read-manga/uso_to_kiss/mf/v01/c006/7/
it says on the bottom someplace. hope that helps(⌒▽⌒)
Mairo and Eiki pair, i like them the most. i want to read Naoyuki Vs Akiomi. And i want Carlos get a lover too.. Hehe___ he isn't a bad guy after all.