For example, the Catechism of the Catholic Church (2357) teaches: "Basing itself on sacred Scripture, which presents homosexual acts as acts of grave depravity, tradition has always declared that homosexual acts are intrinsically disordered. They are contrary to the natural law. They close the sexual act to the gift of life. They do not proceed from a genuine affective and sexual complementarity. Under no circumstances can they be approved."
However, the Catechism (2357-2359) also teaches: "Homosexual persons are called to chastity. By the virtues of self-mastery that teach them inner freedom, at times by the support of disinterested friendship, by prayer and sacramental grace, they can and should gradually and resolutely approach Christian perfection."
In other words, homosexuality itself is not sinful per se. Rather, it is homosexual acts that are sinful.
Now, why think the Catholic Church is right about this? After all, doesn't the American Psychological Association recognize that homosexual behavior is normal? Well, unfortunately for pro-gay rights activists, the APA succumbed to political pressure and the scientific studies simply do not support this conclusion.
For example, J. Michael Bailey, himself an advocate of gay rights, concludes that, "These studies contain arguably the best published data on the association between homosexuality and psychopathology, and both converge on the same unhappy conclusion: homosexual people are at substantially higher risk for some forms of emotional problems, including suicidality, major depression, and anxiety disorder, conduct disorder, and nicotine dependence . . . The strength of the new studies is their degree of control."
What's most striking about this is that Bailey's studies (Commentary: "Homosexuality and mental illness," Arch. Gen. Psychiatry 56, pp. 876-880.) were conducted in the Netherlands, a country highly tolerant of homosexual behavior. This suggests that the mental disorders associated with homosexual behavior are not based on social stigmatism, but are demonstrably correlated.
For those who object that people are born homosexual, that point is moot. People are also born with schizophrenia, but none of us would consider such a condition good or healthy.
The Church should welcome homosexuals into full communion, so long as they abstain from homosexual acts. It may be a struggle, but who among us does not have any struggle?