The UN has voted to approve a non-binding ban on all human cloning, ending two years of wrangling.
The UN has been debating human cloning for two years
The 191-nation assembly voted in favour of the declaration by 84 votes to 34, with 37 abstentions.
Ahead of the vote, the UK government, which voted against the proposal, said it would make no difference to stem cell research in the country.
The non-binding declaration was put to the vote after the UN had failed to reach an agreement on a binding ban.
The US and many predominantly Catholic countries voted in favour of the proposal, arguing that human cloning, even for therapeutic reasons, represented the taking of human life.
But speaking before the result was known, UK Health Secretary John Reid said he was against the proposal, put forward by Honduras, as therapeutic cloning had the potential to help develop treatments for a range of diseases.
Therapeutic cloning is allowed in Britain although reproductive cloning was made illegal in 2001.
Mr Reid said the UK stem cell research industry remained "open for business".
"This [proposal] would deny many patients with illnesses like Parkinson's disease, chronic heart disease and juvenile diabetes, the potential of effective treatments.
"It is a shame that the UN could not agree to a legally binding worldwide ban on reproductive cloning, simply because a small group of countries intransigently refused to allow individual countries to make up their own minds on therapeutic cloning."
And Professor Richard Gardner, chair of the UK Royal Society's working group on stem cells research and cloning, added: "The Royal Society is disappointed that the United Nations has voted in favour of adopting this ambiguous and badly worded political declaration.
"Fortunately, it is non-binding, which means that the UK can continue to pursue the promising avenues of research opened up by the use of carefully regulated human therapeutic cloning."
Professor Arne Sunde, chairman of the European Society for Human Reproduction and Embryology, said: "We don't support human reproductive cloning and that's why we acted early on to introduce a moratorium.
"We have no plans to lift it and we welcome the UN's unanimous decision to ban it.
"But, we strongly support therapeutic cloning and we regret that the UN seems unable to distinguish between these two very different forms and has voted to ban research designed to find treatments for some of the world's most distressing disease."
"We sincerely hope that those countries who oppose therapeutic cloning will not seek to interfere with those countries who are carrying out this vital research."
But Patrick Cusworth, a spokesman for "pro-life" charity Life, said: "It is clear that the vast majority of the world's governments see so-called 'therapeutic' cloning for what it is - the deliberate creation and destruction of human beings.
"The only shame is that Britain, and other countries with money tied up the murky world of human cloning, saw fit to oppose a watertight ban on what is an unethical, unnecessary and dangerous procedure."
Human cloning first came before the UN in 2003 when Costa Rica tabled a resolution calling for the UN to introduce a binding ban on all forms of cloning, including therapeutic.
The resolution was supported by the US and another 64 countries.
Belgium also put forward a proposal to ban reproductive cloning but allow countries to decide for themselves on therapeutic cloning within a regulation framework.
Despite lengthy negotiations, neither resolution has been voted on and last November it was agreed that a non-binding declaration would be explored.
In February, a UN committee voted in favour of the declaration, although the UK voted against it, passing it on to the general assembly.