The long awaited document from the Vatican's doctrinal body marked a big step by the Vatican into the brave new world of biotechnology, an area in which governments around the world are struggling to formulate legislation.
The document also condemned new drugs that block pregnancy from taking hold, such as the so-called "morning-after pill" and the drug RU-486, which blocks the action of hormones needed to keep a fertilised egg implanted in the uterus.
These drugs, as well as the IUD (intrauterine device), which has been in use for decades, were deemed to fall "within the sin of abortion" and are gravely immoral.
"Dignitas Personae (dignity of a person), an Instruction of Certain Bioethical Questions," is an attempt to bring the Church up to date with recent advances in science and medicine.
The document, the most authoritative of its kind from the Vatican in 20 years, said human life deserved respect "from the very first stages of its existence (and) can never be reduced merely to a group of cells."
"The human embryo has, therefore, from the very beginning, the dignity proper to a person," said the Congregation of the Doctrine of the Faith's document, approved by Pope Benedict who headed the same office before his election in 2005.
It said most forms of artificial fertilisation "are to be excluded" because "they substitute for the conjugal act ... which alone is truly worthy of responsible procreation."
Condemning in-vitro fertilization, it said the techniques "proceed as if the human embryo were simply a mass of cells to be used, selected and discarded."
The highly technical document said only adult stem cell research was moral because embryonic stem cell research involved the destruction of embryos. It also condemned freezing embryos.
Governments in countries including the United States are grappling with legislation on embryonic stem cell research.
The outgoing administration of President George W. Bush has placed restrictions on federal funds for embryonic stem cell research but President-elect Barack Obama has promised to lift them.
The 35-page document also attacked the concept of "designer babies," either by pre-implantation diagnosis during in vitro fertilisation where embryos are selected before being transferred to a woman's womb, or in attempts at human cloning in the future.
It branded diagnosis aimed at ensuring that only embryos free from defects or having the desired sex or other particular qualities are transferred into a woman's womb as "shameful and utterly reprehensible".
It condemned the concept of human cloning "to satisfy certain specific desires, for example, control over human evolution, selection of human beings with superior qualities, pre-selection of the sex of a child to be born, production of a child who is the "copy" of another, or production of a child for a couple whose infertility cannot be treated in another way."
Saying life was sacred from the moment of conception to the moment of natural death, the document also defended the Roman Catholic Church's right to intervene on such matters.
"There are those who say that the moral teaching of the Church contains too many prohibitions. In reality, however, her teaching is based on the recognition and promotion of all the gifts which the Creator has bestowed on man: such as life, knowledge, freedom and love," it said.
Do you agree with the Vatican's statement?