"The Church's conscientious effort to resist this pressure calls for a reasoned defense of marriage as a natural institution consisting of a specific communion of persons, essentially rooted in the complementarity of the sexes and oriented to procreation. Sexual differences cannot be dismissed as irrelevant to the definition of marriage.""Marriage is holy, while homosexual acts go against the natural moral law. Homosexual acts close the sexual act to the gift of life. They do not proceed from a genuine affective and sexual complementarity. This same moral judgment is found in many Christian writers of the first centuries and is unanimously accepted by Catholic Tradition.""Such unions are not able to contribute in a proper way to the procreation and survival of the human race.""Civil laws are structuring principles of man's life in society, for good or for ill. They play a very important and sometimes decisive role in influencing patterns of thought and behavior. Lifestyles and underlying presuppositions these express not only externally shape the life of society, but also tend to modify the younger generation's perception and evaluation of forms of behavior. Legal recognition of homosexual unions would obscure certain basic moral values and cause a devaluation of the institution of marriage.""As experience has shown, the absence of sexual complementarity in these unions creates obstacles in the normal development of children who would be placed in the care of such persons. They would be deprived of the experience of either fatherhood or motherhood. Allowing children to be adopted by persons living in such unions would actually mean doing violence to these children, in the sense that their condition of dependence would be used to place them in an environment that is not conducive to their full human development.""The principles of respect and non-discrimination cannot be invoked to support legal recognition of homosexual unions. Differentiating between persons or refusing social recognition or benefits is unacceptable only when it is contrary to justice. The denial of the social and legal status of marriage to forms of cohabitation that are not and cannot be marital is not opposed to justice; on the contrary, justice requires it.""Because married couples ensure the succession of generations and are therefore eminently within the public interest, civil law grants them institutional recognition. Homosexual unions, on the other hand, do not need specific attention from the legal standpoint since they do not exercise this function for the common good.""In those situations where homosexual unions have been legally recognized or have been given the legal status and rights belonging to marriage, clear and emphatic opposition is a duty. One must refrain from any kind of formal cooperation in the enactment or application of such gravely unjust laws and, as far as possible, from material cooperation on the level of their application."In conclusion: "The Church teaches that respect for homosexual persons cannot lead in any way to approval of homosexual behavior or to legal recognition of homosexual unions. The common good requires that laws recognize, promote and protect marriage as the basis of the family, the primary unit of society. Legal recognition of homosexual unions or placing them on the same level as marriage would mean not only the approval of deviant behavior, with the consequence of making it a model in present-day society, but would also obscure basis values which belong to the common inheritance of humanity."