What is an example of a law that is based on one's ancestry?

Finally, what is the case with muta? I feel as though it's an abused concept these days, does a married man need the permission of his wife prior to doing muta? Or can he keep it a secret?

Laws based on ancestry:

1- Inheritance. You inherit only from your biological father, not a stepfather or adopting father.

2- Laws of Mahramiyya

3- Laws of Khums and Zakat. For instance, if your biological father is a Sayed then you are entitled to Khums.

4- Obedience to parents. You have an obligation towards your biological father in terms of obedience.

5- Spending. You are obligated to spend on your biological father if he is struggling financially.

And the list goes on

Mut’a has many dimensions and consequences. In brief, he legally does not need his wife’s permission. Yes, if during the marriage contract (Aqed or Nikah) she stipulated as a condition that he would need her permission, then he would. Otherwise he does not.

Ayatollah Sistani says if the woman he wants to do Mut’a with is not Muslim (Christian), then he needs his wife’s permission. But if she is Muslim, then he doesn’t. Other Maraje’ say you don’t need your wife’s permission if you want to do Mut’a with a Christian girl.