Excerpt from the Church's document on certain issues regarding procreation, Dignitas Personae: On Certain Bioethical Questions (September 2008). Here is part of the conclusion. (The numbers below correspond to the numbers at the beginning of each section in the official document).
36. There are those who say that the moral teaching of the Church contains too many prohibitions. In reality, however, her teaching is based on the recognition and promotion of all the gifts which the Creator has bestowed on man: such as life, knowledge, freedom and love. Particular appreciation is due not only to man's intellectual activities, but also to those which are practical, like work and technological activities. By these, in fact, he participates in the creative power of God and is called to transform creation by ordering its many resources toward the dignity and well being of all human beings and of the human person in his entirety. In this way, man acts as the steward of the value and intrinsic beauty of creation.
Human history shows, however, how man has abused and can continue to abuse the power and capabilities which God has entrusted to him, giving rise to various forms of unjust discrimination and oppression of the weakest and most defenseless: the daily attacks on human life; the existence of large regions of poverty where people are dying from hunger and disease, excluded from the intellectual and practical resources available in abundance in many countries; technological and industrial development which is creating the real risk of a collapse of the ecosystem; the use of scientific research in the areas of physics, chemistry and biology for purposes of waging war; the many conflicts which still divide peoples and cultures; these sadly are only some of the most obvious signs of how man can make bad use of his abilities and become his own worst enemy by losing the awareness of his lofty and specific vocation to collaborate in the creative work of God.
At the same time, human history has also shown real progress in the understanding and recognition of the value and dignity of every person as the foundation of the rights and ethical imperatives by which human society has been, and continues to be structured.
Precisely in the name of promoting human dignity, therefore, practices and forms of behaviour harmful to that dignity have been prohibited. Thus, for example, there are legal and political—and not just ethical—prohibitions of racism, slavery, unjust discrimination and marginalization of women, children, and ill and disabled people. Such prohibitions bear witness to the inalienable value and intrinsic dignity of every human being and are a sign of genuine progress in human history. In other words, the legitimacy of every prohibition is based on the need to protect an authentic moral good.