The Vatican newspaper said yesterday that homosexuality risked "destabilising people and society", had no social or moral value, and could never match the importance of the relationship between a man and a woman.
The remarks were contained in a long commentary published to accompany the official statement on homosexuality and the priesthood.
The article by Mgr Tony Anatrella, a French Jesuit and psychologist, said homosexuality could not be considered an acceptable moral alternative to heterosexuality.
"During these past years, homosexuality has become a phenomenon that is always destabilising reality and in many countries is considered a quality that is normal," the article in L'Osservatore Romano said.
The article was specifically approved by the Vatican's secretariat of state.
"It [ homosexuality] does not represent a social value and even less so a moral virtue that could add to the civilisation of sexuality," Mgr Anatrella said.
"It could even be seen as a destabilising reality for people and for society."
The Catholic Church, the article said, had a duty to reaffirm its position that homosexuality is "against conjugal life, the life of the family, and priestly life".
"In no case is this form of sexuality a sexual alternative, or even less, a reality that is equivalent to that which is shared by a man and a woman engaged in matrimonial life," the Italian-language article said.
"It [ homosexuality] cannot be encouraged or even less so, supported with pastoral initiatives," it said in an apparent reference to Catholic priests who administer to homosexuals without reminding them of the church's position against gay sex.
It said homosexuality was "a sexual tendency and not an identity" and repeated the church's stand against allowing gays to marry or to adopt children.
The article also called homosexuality "an incomplete and immature part of human sexuality". - (Reuters)