>>510354091 (OP)It should be LEGAL and we should talk openly about it.
It's already rare or at least not common by default due to nature and it's tatics. You usually will not feel attracted by yout mother or sister.
Happens that sometimes, love comes in diferent forms. And in my book it's ok as long both sides consent and cum.
About pregnancy, there is multiple ways to avoid it.
And even if it happens ONCE in the lineage, it does not mean that would happen again in the next generation.
Here is an example of my superior IQ:
1 GEN - Incest happens and there is preg. There is a risk about it but the risk is not that absurd so the kid born quite ok.
2 GEN - Incest is allowed but pregnancy must be avoided at all cost.
Now, on this generation, it mix with another family and genetic to purge the nature Debuff.
3 GEN - Now that we jumped one genration and mixed, pregnancy is allowed again and Incest is allowed again.
As you can see, if the risk is controlled and there is a cleat tatic to hack it, Incest is 100% possible and Ok.