Beliefs have changed over time, and stubbornly adhering to a philosophy that has existed for two millennia will do nothing but meet resistance to modern beliefs.
Here are some examples:
Gay marriage - The Bible specifically forbids this, but the majority of people in the United States (Which is a primarily Christian country) support Gay rights.
Abortion - Same as Gay marriage.
Divorce - Same as Gay marriage.
Gender equality - Read some of these excerpts from the Bible. Pretty self explanatory if you're living in this decade.
"But I would have you know, that the head of every man is Christ; and the head of the woman [is] the man; and the head of Christ [is] God."
"For the man is not of the woman; but the woman of the man. "
"Let your women keep silence in the churches: for it is not permitted unto them to speak; but [they are commanded] to be under obedience, as also saith the law. "
"And if they will learn any thing, let them ask their husbands at home: for it is a shame for women to speak in the church."
"Wives, submit yourselves unto your own husbands, as unto the Lord. "
"And Adam was not deceived, but the woman being deceived was in the transgression. "
I believe that Christianity should adapt to modern values. We no longer live in the stone age and certain morals are out of date. As the world becomes more progressive so should any religion not just Christianity. For example the bible teaches that women should be submissive and obey men, but in 2013 women have the same opportunities as men and many lead the household. That's just one example, but there are many more.
If God is all knowing, and true believers believe this, He would have seen the changes in the future. He gave us His word in the Holy Bible with nothing stating 'as long as the country agrees with this'. In fact, the Bible says the exact opposite in Malachai 3:6 "For I am the Lord, I change not." If the opposite were true, the God of all creation would have said so. Only modern man who want immoral actions says differently. I walk with God.