A common belief in our secular society, is that the Church should "update" her moral teachings. Why, some may ask, does she hold on to outdated teachings such as abortion, contraception, same-sex unions, and divorce, among many others?
As John Paul II explains in Veritatis Splendor, which is his encyclical on moral teachings, the Church dervies her moral teachings from Christ himself. She is not at liberty to change them when society itself changes because Christ gave these teachings to the Church.
Take time to read reliable resources concerning the Church's moral teachings that will hopefully answer any questions about why the Church teaches what she does.