Vatican City ? The Vatican hardened its opposition Friday to using embryos for stem cell research, cloning and in-vitro fertilization. But in a major new document on bioethics, it showed flexibility on some forms of gene therapy and left open questions surrounding embryo adoption.

The Vatican’s Congregation for the Doctrine of the Faith issued “The Dignity of a Person” to help answer bioethical questions that have emerged in the two decades since its last such document was published.

With it, the Vatican essentially confirmed in a single, authoritative instruction the opinions of the Pontifical Academy for Life, a Vatican advisory body that has debated these issues for years.

The Vatican’s overall position stems from its belief that human life begins at conception and must be given the consequent respect and dignity from that moment on. The Vatican also holds that human life should be created through intercourse between husband and wife, not in a petri dish.

As a result, the Vatican said it opposed in vitro fertilization and related technologies because it involved separating conception from the “conjugal act” and often results in the destruction of embryos.

But it stopped short of issuing an explicit no to “embryo adoption,” whereby infertile couples adopt embryos that were frozen during in vitro techniques and subsequently abandoned. It said that while the intent was “praiseworthy,” the result posed legal, medical and psychological problems.

Dr. Edmund Pellegrino, emeritus professor of medicine and medical ethics at Georgetown University and the chairman of the President’s Council on Bioethics, said that vagueness indicated that the question of embryo adoption “is still a little bit open.”

“That means we’re not issuing dicta on things which may be questionable,” he said in an interview from Washington.

He said the document was valuable not because it contained any new pronouncements, but because it made explicit, and in one authoritative place, Vatican positions on issues that have emerged since the last such document was published in 1987, “Donum Vitae,” or “Gift of Life.”

“The important thing is the linking (of the scientific advances) with the dignity of the human person, and the notion of the church’s teaching on procreation,” he said.

The Vatican said it opposed the morning-after pill, even if it doesn’t cause an abortion, because an abortion was intended. That could complicate the situation of some Catholic hospitals in the United States that offer the morning-after pill to rape victims.