The Bible does not address this issue because it was not around at the time. But, No, sex change operations are not okay. God created people as male and female (Gen. 1:27). People are ordained by God to be male or female because it is He who forms them in the womb:
- Isaiah 44:2, "Thus says the Lord who made you and formed you from the womb, who will help you, Do not fear, O Jacob My servant; and you Jeshurun whom I have chosen."
- Isaiah 44:24, "Thus says the Lord, your Redeemer, and the one who formed you from the womb, 'I, the Lord, am the maker of all things...'"
Therefore, to change the gender of a person through an operation is a violation of the natural birth gender that God has ordained for the person. It also violates the distinction of those attributes which designate a male from a female. Furthermore, if, for example, a male becomes a woman and has relations with a male, then this would be homosexuality another sin clearly forbidden by scripture.
If anything, this sexual identity dysfunction is due to sin in the world. Transsexuals (those who have changed sexes) and claim to be Christian cannot appeal to the problem of a "biological goof" due to sin in the world. It is due to sin and its effects that such an issue of transsexualism even exists and an appeal to a sinful state should never excuse further sin.
Nevertheless, we are not to abandon the transsexual. Even though the person is in sin, the transsexual is still a person in need of full redemption, love, grace, and kindness. We do not convince someone to repent by condemning and accusing. Rather, they need to see the love of Christ in us so that His presence might convict and convince them of their sin.