Sex change is defined as “changing the sex of a male into female, a female into male, neutral into male, neutral into female, male into neutral, or female into neutral.” The general definition of sex change covers animals and even plants. There is a great disagreement on sex change in transsexual persons. Some Shi'a jurisprudents hold that it is lawful. In contrast, all Sunni scholars hold that it is unlawful. Of course, some of the Shi'a jurisprudents have changed their views and believe that it is unlawful. In the view of those Shi'a scholars who believe that sex change is lawful, there is no reason for unlawfulness of this new phenomenon.
One of the most important arguments of those who hold that sex change is unlawful – considering the Sura Al-Nisa`, chapter 4, verse 119 - is unlawfulness of transformation of God’s creation. Referring to exegesis books it is made clear that essentially this verse does not pertain to the modern issue of sex change. Some other jurisprudents rely on Sura Al-Shuara, chapter 42, verse 49 to prove unlawfulness of sex change. In response to this argument, it seems that sex change is a possible matter and in the case or gender reassignment the religious law for the opposite sex is applicable to him/her. Another argument relied on by the jurisprudents is Sura Al-Nur, chapter 24, verse 30. It seems that this Sura also does not pertain to the unlawfulness of sex change. In the view of Imam Khomeini and some other jurisprudents, sex change is not unlawful, but it invalidates the previous marriage and changes family titles as well as the legal share of inheritance of transsexual based on the newly reassigned gender.