Disownment by parents means to do an act that would make them angry, cause them distress and injure their feelings.  Certainly, hurting one of them also causes the child to be disowned.[1] Although parents enjoy special respect in all religions and cultures, Islam has enumerated, over and above to the rights considered by other religions, a wide range of moral rights for the parents. The rights considered by Islam for the parents are so extensive that even hurting them is regarded as a kind of violating their rights. In addition to the moral rights, Islam has considered a number of jurisprudential rights for the parents which a child should uphold and fulfill. For example, if a child's parents are needy and helpless, it is obligatory on him to take care of them and pay for their maintenance (food, clothing and medical expenses).[2]

There are different interpretations relating to the parents' rights on the child.  For example, God, the Exalted, says:

"And your Lord has commanded that you shall not serve (any) but Him, and goodness to your parents. If either or both of them reach old age with you, say not to them (so much as) "Ugh" [fie] nor chide them, and speak to them a generous word."[3]

As it is clear from the above verse, in addition to belief in God and not ascribing any partners to Him, God, the Exalted, has commanded us to be kind to our parents and not to cause them distress by even using a word of contempt while talking to them. Although the narrations have counted disownment by the parents as one of the great sins[4], they have not fixed any limits for it in the same way as the Quranic verses. The narrations simply state that causing distress and discomfort to the parents is forbidden.[5]

Hence, therefore if an action causes distress to the parents, it can be considered as a criterion for violating parents' rights.[6]  If a child disagrees with his parents on some matters which cause them distress, he has provided the means for his disownment by his parents. However, sometimes disagreeing with parents or disobeying them is not severe to the extent that may cause them distress, in this case it is better for him to act in accordance with their opinion.

Yes, there are various cases which are not considered to be a part the child's obligation to obey his/her parents. For example, if a man's parents order him to do an act which is against the divine command or religious and Islamic law, it is not necessary for him to obey them. This disobedience does not cause the child to be disowned.[7]

Therefore, we can conclude that the criterion with respect to the parents' rights is to fulfill their demands to the extent that not doing them does not morally cause them distress and discomfort and that their orders should not involve doing a religiously forbidden act or avoiding an obligatory one. Certainly, there are certain acts which are not obligatory but it is better, not wajib, to get the parents' consent in them.  In order for a person to know the Islamic viewpoint about each case, one should refer to his own Marja' (the religious authority whom he follows) and act according to his fatwa (verdict).