A 15-year-old Icelandic girl has won the right to keep her first name, despite it being "unapproved" by the state. Why do some countries restrict baby names?

Parents-to-be often find it hard enough to find a name they both like, let alone one the state might also be in favour of.

Bjork Eidsdottir had no idea when, in naming her newborn girl Blaer 15 years ago, she was breaking the law.

In the eyes of the authorities Blaer, which means "light breeze", was a male name and therefore not approved. It meant that for her entire childhood, Blaer was known simply as "Girl" on official documents.

But Reykjavik District Court ruled on Thursday that it could indeed be a feminine name.

"Finally I'll have the name Blaer in my passport," she said after the ruling.

The answer the most common reason is to save the child potential embarrassment

the risk of confusion is also a factor

some countries have rules about names being gender specific or meeting grammar rules

numbers are also often banned

Several countries - such as Germany, Sweden, China and Japan - also restrict names. Why?

In the case of Iceland, it's about meeting certain rules of grammar and gender, and saving the child from possible embarrassment. Sometimes, although not in every case, officials also insist that it must be possible to write the name in Icelandic.

There is a list of 1,853 female names, and 1,712 male ones, and parents must pick from these lists or seek permission from a special committee.

Similar concerns about child welfare are present in Germany, where a Turkish couple were not allowed to call their baby Osama Bin Laden.

One couple named their baby Berlin after the city in which they met, prompting the registrar to mount an objection. He eventually relented after the family's lawyer pointed out that the courts had allowed the name London.

Your name's not allowed... Iceland Yes: Elvis

Elvis No: Carolina New Zealand Yes: Number 16 Bus Shelter

Number 16 Bus Shelter No: Yeah Detroit Germany Yes: Legolas

Legolas No: Matti Sweden Yes: Metallica

Metallica No: Brfxxccxxmnpcccclllmmnprxvclmnckssqlbb11116 Japan No: Akuma (means Devil) Portugal No: Mona Lisa Denmark, France, Spain and Argentina also strict

Gender confusion prevented a German boy being Matti, because the sex of the baby wouldn't be obvious. And you won't find any Germans named Merkel, Schroeder or Kohl, either, because surnames are banned as first names.

The name 4Real fell foul of authorities in New Zealand, because names cannot start with a number.

A judge there also made a young girl a ward of court so that she could change the name she hated - Talula Does The Hula From Hawaii.

When Japanese parents register their newborns, the local authorities can say no if they don't think the name is appropriate. In 1993, the name Akuma, meaning "devil", was not permitted.

And in China, people have been forced to change their names because they were deemed too obscure.

The UK and the US have much more liberal naming laws.

American parents can pretty much name their child anything, says Michael Sherrod, co-author of Bad Baby Names: The Worst True Names Parents Saddled Their Kids With.

In fact, he says, parents see it as an important expression of their freedom of speech, enshrined in the US Constitution.

"When I discovered the restrictions that other countries have, I was absolutely astounded."

Unusual American names Female

Enamel

Lettuce

Mustard M Mustard

Vagina

Mutton

Post Office

...and others too obscene to mention

Strange names are nothing new, he says. Census records in the 18th and 19th Centuries revealed people named King's Judgement, Noble Fall and Cholera Plague.

"In all, there have been 20 people named Noun, 458 named Comma, 18 called Period but only one called Semicolon."

Getting on to more risque territory, Ima and Wanna are also popular, especially with surnames like Mann, Hoare or Pigg, he says. More offensive names have also been allowed.

But why would parents do that to their children?

"A lot of parents say they want their kids to be unique. They think it's fun and differentiates their child from everyone else, and gives them a personality," says Sherrod.

"Americans are also very proprietary about their children and take the attitude, 'We can do whatever with our children and if they don't like it they can change it when they're older.'"

Children with unusual names tend to get a lot of abuse at school but then embrace it when they're older, he says.

What's the picture in the UK? A spokesman for the General Register Office says there are no restrictions on parents - except for exceptional cases, such as a name which could be deemed offensive, when an official could refuse to register it

Superman, Perri 6 and long names containing all members of a football team permitted What can you name your child in the UK?

There is no question that some of the more offensive names could be considered as child abuse, but that doesn't mean legislation is the answer, says Sherrod.

"I'm not saying courts should not intervene, but I would prefer they do so only when parents cannot agree and the item gets taken to court.

"I think, for the most part, parents are pretty good at compromise. I would say, anecdotal evidence is that the number of cases considered abusive is so tiny as to not require much law, if any."

But courts have stepped in on occasion.

When Thomas Boyd Ritchie III tried to change his first name to III, he was told by a court in California it would be "inherently confusing".