Would it be incest if the boy to the left fucked his trap sister (to the right)?

>it is impossible for her to become pregnant since she has balls and not ovaries so the reason why incestuous relationships are frown upon does not apply
>it wouldn't even be gay since she's a girl

The old greeks fucked their brothers all the time while fucking their sisters were a no-go since the offspring had a pretty fair chance of becoming retarded. The old greeks did totally fine until they became cucked by a dead jew on stick