>>590431Women are more disgusted by incest than men according to studies. This makes sense because making a mistake in choosing a mate is very costly for a woman. Women who spent 9 months and more investing in an incestuous offspring with a higher chance of defects would have had a lower long term gene survival rate than women who didn't.
Men on the other hand can knock up their sister without that much psychical consequence. Only their society could create a possible consequence, as an extension of protecting the woman's interests, and also the tribe's interest in her fertile womb. Men are also disgusted by it, but not to the same extent (degozaru)