The report said the Simpsons are banned to avoid the promotion of Western culture, but Superman and Spider-Man are allowed, because they helped the "oppressed".

"We do not want to promote this cartoon by importing the toys," Mohammad Hossein Farjoo, secretary of policymaking at the Institute for the Intellectual Development of Children and Young Adults, told the Shargh daily newspaper.

He did not elaborate on what was wrong with the Simpsons specifically, but he said that any doll on which genitals are distinguishable, as well as dolls of adults, are banned.

So are toys with speakers that blare out the voices of Western singers, or toy kitchen sets which include glasses for drinking alcoholic beverages.

Mr Farjoo went on to say that Spider-Man and Superman dolls are authorised for sale, adding: "They help oppressed people and they have a positive stance."

In 1996, the agency called Barbie dolls a "Trojan horse". In January, police said they closed down dozens of toy shops for selling Barbies.

Since the 1979 Islamic revolution that ousted a pro-Western monarchy, Iran has tried to fight Western cultural influence.

Despite bans on many books, films, satellite TV channels, music, haircuts and fashion from the West, many young people follow Western culture avidly and can often obtain illegal products on the black market.

In 2011, Iran imported 57 million US dollars (£36 million) worth of toys. Officials believe another 20 million dollars (£12.6 million) worth of toys were smuggled across the border in the same year.