this show is so fake

who would do it with their own sister ?

Well, this anime got some logic to support twincest tendency, as Sora said, they are special, but in term of being separated quite some time since childhood.

Siblings/Fraternal twins incest: lack of westermarck effect suppression, therefore genetic sexual attraction kicks in.

Do you people have the BD version?
Coz it has a lot of uncensored scenes which not shown in TV version...