[Valpal1]

You seem to be unaware that consanguinous marriage (inbreeding) is a common cultural/tribal bad habit world wide.

The proscription or cultural taboo on it in western culture derives directly from the biblical prohibition of it.

[Alouette]

The proscription or cultural taboo on it in western culture derives directly from the biblical prohibition of it.

The Bible does not prohibit first cousin or even uncle/niece marriages, in fact seems to encourage it.