The world could get its first lab-grown burger this year, with scientists using stem cells to create strips of beef. But could vegetarians eat it?

Scientists in the Netherlands hoping to create a more efficient alternative to rearing animals have grown small pieces of beef muscle in a laboratory.

These strips will be mixed with blood and artificially grown fat to produce a hamburger by the autumn.

The stem cells in this particular experiment were harvested from by-products of slaughtered animals but in the future, scientists say, they could be taken from a live animal through biopsy.

One usually assumes the main motivation for vegetarianism - aside from those who practise for religious reasons - is about the welfare of animals. The typical vegetarian forswears meat because animals are killed to get it.

So if the meat does not come from dead animals would there be an ethical problem in eating it if it one day lands on supermarket shelves?

It's not as simple an equation as that, says Prof Andrew Linzey, director of the Oxford Centre for Animal Ethics. He says the burger as currently envisaged isn't an acceptable substitute for vegetarians, but is still a step forward.

People who are vegetarian for moral reasons - the environment, the treatment of animals - have a moral obligation to eat this meat Prof Julian Savulescu , Director of the Oxford Uehiro Centre for Ethics Synthetic meat grown in Dutch lab

"Synthetic meat could be a great moral advance. It won't be suitable for vegetarians because it still originates in meat by-products, but bearing in mind that millions of animals are slaughtered for food every day, it is a step forward to a less violent world."

According to the Vegetarian Society, a vegetarian does not eat "any meat, poultry, game, fish, shellfish or crustacea, or the by-products of slaughter".

The lab-grown meat created so far has been grown from stem cells taken from foetal calf serum. This is usually a by-product of slaughter, although stem cells could be harvested in smaller volumes without killing animals.

Prof Julian Savulescu, the director of the Oxford Uehiro Centre for Ethics, says it doesn't matter how the product is made and "the fact that the meat is made from animal by-products is morally irrelevant".

"People who are vegetarian for moral reasons - the environment, the treatment of animals - have a moral obligation to eat this meat.

"They need to do this because it will contribute to an ethical alternative to conventional meat."

For many vegetarians though, the issue is a complicated one.

"Some are waiting with bated breath, keen to experience the taste and texture of meat without actually harming an animal, while others find the whole idea utterly repulsive," says Su Taylor from the Vegetarian Society.

Image caption Beef stem cells are being grown to make the first laboratory burger

The UK Food Standards Agency's Public Attitudes to Food survey of 3,219 adults in 2009 found 3% of respondents were "completely vegetarian" and an additional 5% "partly vegetarian (don't eat some types of fish or meat)".

Just because the meat has been grown artificially doesn't mean it is vegetarian, says Vegetarians International Voices for Animals (Viva). But Viva insists vegetarianism and veganism aren't religions so individuals should make up their own minds.

"Certainly, with over 950 million land animals slaughtered in the UK each year," says Viva spokesman and campaign manager Justin Kerswell, "and the vast majority of them factory farmed in awful conditions, anything that saves animals from suffering is to be welcomed."

There's already been discussion about whether meat eaters could be persuaded to eat the artificial meat, but at the moment the price tag is likely to be prohibitive. The first lab-grown burger is likely to cost in the region of £200,000 to produce.

Savulescu says most people won't give up meat, but if there was a palatable alternative, conventional meat eaters might move to it.

"Moral vegetarians need to promote, use and consume this test tube meat," Savulescu said. "Then it will become cheaper."

A vegetarian does not eat any meat, poultry, game, fish, shellfish or crustacea, or the by-products of slaughter Vegetarian Society definition

The research on artificial meat has been prompted by concerns that current methods of meat production are unsustainable in the long term.

But to Kerswell, the research seems unnecessary, particularly as many vegetarians believe a diet excluding meat is more healthy.

"Why grow it in a Petri dish or eat the meat from a slaughtered animal when plant sources of protein and meat replacements are ever more commonly available and are better for our health?"

Of course, there are plenty of nutritionists who speak of the value of eating some meat. Dr Elizabeth Weichselbaum, a nutrition scientist at the British Nutrition Foundation, says meat is an important source of a number of nutrients in our diet, including high quality protein, iron, zinc, selenium, vitamin D and some B vitamins.

"It can make an important contribution to a healthy and balanced diet. Meat and other protein sources, including eggs, beans and nuts, should be eaten in moderate amounts."

So could vegetarian chefs be persuaded? Denis Cotter, who runs a vegetarian restaurant in Cork, Ireland, says "after an instinctive shudder of revulsion" he can see the benefits of the burger, but it won't be making its way on to any of his menus.

"Personally, I don't like synthetic food, and avoid all that soy-based fake meat stuff aimed at vegetarians. So, no, I wouldn't be interested in using it, either as a restaurant product or on my plate at home. But I would back it as a better way to produce meat than burning down rainforests and gobbling up useful farmland."