The USCCB has released a letter that covers a range of family and life issues including homosexuality and contraception. The letter, titled Marriage: Love of Life and the Divine Plan reaffirms many Church teachings that even many Catholics prefer to view with a blind eye.
A core theme is that marriage is not a purely human institution but was given to us by God. Because of this, we are not at liberty to make changes to what marriage is, “the lifelong partnership of the whole of life, of mutual and exclusive fidelity, established by mutual consent between a man and a woman, and ordered towards the good of the spouses and the procreation of offspring” (CCC 1601). Marriage is a gift from God, not a human invention that we can change if we so desire.
If you’re looking for a true, helpful, and clear explanation of why the Catholic Church teaches what she does about divorce, contraception, cohabitation, homosexuality, and many other topics then this letter is for you.