This paper looks at the ethics of assisted reproductive technology (ART) from the perspective of the Catholic Church. The three criteria of evaluation of the ethics of ART are the right to life and physical integrity of human beings, the unity of marriage, and the value of human sexuality. The paper examines the arguments based on these criteria carefully, as they apply to in vitro fertilization which is the most common ART method. It concludes that most ART methods would be unacceptable, but there are new alternatives like NaProTechnology that is promising for infertile couples.