The Catholic church does not believe in using contraception because they think it is a form of abortion. That belief is not true. Contraception prevents pregnancy and lowers the risk of sexually transmitted diseases. The birth control pill has also been shown to lower the risk of many health factors in women.
As a large religious institution that has a single, tangible leader and a legitimate leadership group not comprised of charlatan 'preachers' and other profiteers of ignorance and fear, the Catholic church should use its unique position to join the rest of the world in realizing the huge benefits to contraception. No case needs to be made about the benefits to society that having children at the 'right time' brings, and large, monolithic organizations like the Catholic church could affect positive change worldwide by supporting birth control methods used by advanced societies for 50+ years.
Yes, the Catholic Church should change its stance on contraception. I do not think that doing so would be in contradiction with church doctrine. The official church stance on environmental issues points to sustainability and not harming the environment. Reducing or maintaining a stable population through contraception would fit in nicely with those goals.
Yes, the catholic church does not need to be against the use of contraception, since there are a lot of teens and others in the church that do not need to have a child right now, but they will also not be able to fight back having sex, so they need this.
I do not believe the Catholic Church should change its stance on contraception. I believe it is odd for a church to declare certain beliefs about contraception when there is no mention of it in the Bible, but they shouldn't change their long held beliefs simply from being pressured by the outside world.
Speaking from a purely libertarian viewpoint, if you are not Catholic why do you even care? No one is forcing you, or anyone else, to be Catholic and you are not beholden by the laws of man to follow what the Catholic church teaches.
If you ARE a Catholic, I would say stop being a cafeteria catholic and celebrate with joy our 2000 year old traditions. Look at the 41,000 + Protestant denominations who cannot agree on the color of crap, and look at the shallow morally relativistic world we live in, and then Praise God for his Church standing firm for thousands of years.