The Roman Catholic Church slams the moral door on many modern reproductive technologies in a new "instruction" to researchers, medical personnel and married couples who want children.

The document, released yesterday, updates and expands church teachings, and gives the force of papal authority to strictures against embryonic stem cell research and abortion. It also says that efforts by infertile couples to adopt and implant embryos is just as wrong as destroying embryos for stem cell research.

"The desire for a child cannot justify the 'production' of offspring, just as the desire not to have a child cannot justify the abandonment or destruction of a child once he or she has been conceived," the document says.

However, the church officially throws up its hands over what to do with abandoned embryos, which it says "represent a situation of injustice which in fact cannot be resolved."

Diagnosing embryos for genetic flaws or disease before implantation is "shameful and reprehensible." Such acts, like prescribing or using devices or drugs that prevent an embryo from implanting in the uterus, all lead to "the sin of abortion," it says.

"Dignitas Personae (Human Dignity): On Certain Bioethical Questions" was released in Rome by the Congregation for the Doctrine of the Faith.

The document is available at www.usccb.org.

This is the first time since 1987 that a pope has signed off on an authoritative document on biomedical reproductive technologies.

"Back then we didn't have 500,000 frozen embryos. No one was talking about embryonic stem cell research or pre-implantation embryonic diagnosis," said John Haas, president of the National Catholic Bioethics Center in Philadelphia, who was familiar with an advance text.

Haas says even some practicing Catholics may be surprised by the hard stance against in vitro fertilization and embryo adoption, because "most Catholics believe the church wants them to have a lot of children."

Steve Bozza, who deals with outreach to infertile couples for the Diocese of Camden N.J., says this is still a very touchy issue for infertile Catholic couples.

"They probably know the church's teachings, but the pain people suffer when they can't conceive causes them to turn inward. The church is the last place they go. They go to their physicians, who offer them immoral choices."

The church's stance is based on its interpretation of "natural law," rather than Catholic theological tradition. The idea is that these are truths any culture can agree on, not Catholics alone.

"We are not imposing a Catholic vision on America. We are offering a more human vision," says Richard Doerflinger, head of pro-life activities for the U.S. Conference of Catholic Bishops.