The question is really worded incorrectly. The issue is not what the church thinks; the issue is what the Bible says. Furthermore, we have to ask, which Christian church is referred to in the question? Is it the Roman Catholic Church, the Episcopalian Church, the Baptist Church, or any other denomination? An earthly religious organization doesn't make a church a real church. The true Christian church is not a set of denominational buildings, priests, pastors, and rituals.
Biblically, the church is a collection of the truly saved--of those who have been called out of the sinful world by God's choice (Jude 1; 1 Cor. 1:24, Rev. 17:14) and are now believers who have been regenerated by the work of God and made new creatures (2 Cor. 5:17). So, when we ask the question, "if the church can change its view . . . " we have to ask which "church" is being spoken of; otherwise, we really can't deal with the question sufficiently. Nevertheless, we can still address some of the issues related to the question.
There are some difference in teachings in the Bible in the Old and New Testament. For example, in the Old Testament animal sacrifices were necessary but that is no longer true for the teachings of the New Testament. This is because the sacrifice of Christ did away with the necessity for sacrifices of animals. In the Old Testament, keeping The Law was necessary in order to be right with God but not so in the New Testament. This is because Jesus fulfilled all the requirements of The Law, and now we are right with God by faith in what Christ did, not what we do (Rom. 4:1-5; 5:1). So, God does change His procedures between the Old and New Testament, but He does so based upon the work of Christ. The same work does not invalidate the condemnation of homosexuality.
Homosexuality is spoken against in both the Old Testament and the New Testament.
- Lev. 18:22, "You shall not lie with a male as one lies with a female; it is an abomination."
- Lev. 20:13, "If there is a man who lies with a male as those who lie with a woman, both of them have committed a detestable act; they shall surely be put to death. Their bloodguiltness is upon them."
- 1 Cor. 6:9-10, "Or do you not know that the unrighteous shall not inherit the kingdom of God? Do not be deceived; neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor homosexuals, 10nor thieves, nor the covetous, nor drunkards, nor revilers, nor swindlers, shall inherit the kingdom of God."
- Rom. 1:26-28, "For this reason God gave them over to degrading passions; for their women exchanged the natural function for that which is unnatural, 27and in the same way also the men abandoned the natural function of the woman and burned in their desire toward one another, men with men committing indecent acts and receiving in their own persons the due penalty of their error. 28And just as they did not see fit to acknowledge God any longer, God gave them over to a depraved mind, to do those things which are not proper."
As you can see, homosexuality is still a sin in the New Testament Scriptures of 1 Corinthians and Romans attest. Therefore, the "Christian church" cannot rightfully change its view on the sinfulness of homosexuality and remain Biblical.
Still, there will be those who claim to be Christians who will be seduced by the sinfulness of the secular world and adopt the unbiblical teachings that homosexuality is perfectly normal and not sinful. All who would do so are in violation of God's Word and are probably not really Christians since they willingly violate God's Word.
God created Adam and Eve. He created a man and a woman and gave them the command to multiply and fill the earth (Gen. 1:27-28). This command necessitates biological reproduction, which can only be accomplished between male and female and not between male and male and female and female. In this, homosexuality is an attack on the command of God Himself.
Also, Jesus is God in flesh (John 1:1, 14; Col. 2:9), was born under the law (Gal. 4:4) and within the marriage relationship of a man and a woman (Joseph and Mary). Therefore, God was authenticating the validity of marriage between a man and woman since it was in such a marriage that the Messiah arrived among us. This is His stamp of approval on marriage at the time of Christ, just as he approved of it in the Garden of Eden.
So, homosexuality is, ultimately, an attack upon the mandate of God to fill the earth as well as the sanctity of marriage between a man and a woman. No church has the right to make such an attack. No true church would dare to do so.