Catechism of the Catholic Church §2295 — excerpt
Research or experimentation on the human being cannot legitimate acts that are in themselves contrary to the dignity of persons and to the moral law.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.