In the Church’s view same-sex “marriage” is not a civil right. A strong desire does not make a civil right.
Every man and every woman has a right to enter into marriage, but marriage as an institution can only be between a man and a woman. Governments do not have the power to define marriage otherwise, because it is a permanent human institution that does not owe its existence to governments. Same-sex “marriage” is not a civil right because same-sex couples cannot fulfill the core public purpose of marriage: protecting children by bringing men and women into the only kind of union that can make new life and give children mothers and fathers.
This is not only the Church’s view. Throughout all of human history marriage has been held to be a union of man and woman. Marriage has its roots in natural law, which transcends all man-made law. Marriage as a union of a man and a woman is a natural, universal human institution that unites mothers and fathers in the work of childrearing and family life. Same sex unions may represent a new and a different type of institution – but it is not marriage and should not be treated as marriage.