VATICAN CITY -- Pope Benedict XVI said yesterday that embryos developed for in vitro fertilization deserve the same right to life as fetuses, children, and adults -- and that that right extends to embryos even before they are transferred into a woman's womb.
The Vatican has long held that human life begins at conception, but Benedict's comments were significant because he specified that an embryo in its earliest stages, when it is just a few cells, is as much a human life as an older being.
The pope made the comments during an audience with members of the Pontifical Academy for Life, who opened a Vatican-sponsored conference yesterday on the ethics surrounding the handling of embryos before they are implanted during in vitro procedures.
The Vatican opposes in vitro procedures because some embryos created in a laboratory are often discarded, whereas others are frozen, and still others are created solely for experimentation or to create stem cells.
Benedict repeated the position of the Roman Catholic Church that life begins at the moment of conception and deserves to be respected and protected from that moment on, a position set out most authoritatively in the 1995 encyclical ''Evangelium Vitae."
That encyclical did not specifically address the status of an embryo before it is implanted after in vitro fertilization, the two or three days of growth in a laboratory during which the fertilized egg is dividing into a group of cells that are transferred by a doctor into a woman's uterus.
Benedict made clear that there should be no moral distinction between an embryo before implantation and after, even though he acknowledged that there is no explicit teaching on the first days of life in Scripture.
''The Magisterium of the church has constantly proclaimed the sacred and inviolable character of every human life, from its conception to its natural end," he said.
''This moral judgment is valid already at the beginnings of life of an embryo, before it is implanted in the womb of the mother, who will care for it and nourish it for nine months until the moment of birth," he said.
While there is no consensus among scientists about when life begins -- and thus deserves legal protection -- many scientists believe life starts when the first neurological tissues are evident, about two to three weeks after fertilization, said Dr. Jacques Cohen, a reproductive scientist in New York who was not at the conference.
''Scientists draw lines at different points," said Cohen, who runs the largest pre-implantation genetic diagnosis group in the United States, Reprogenetics, as well as the Galileo Research Laboratories, which researches embryonic development.