A journalist has defended the accuracy of his book that quotes Queen Sofia criticizing gay marriage.

The book has irked the royal palace.

Spain's king and queen are largely respected as figurehead representatives of the state, and rarely speak out on political or social issues.

Veteran journalist Pilar Urbano released the book — "La Reina muy de cerca," or "The Queen, very close up," — this week to mark the queen's 70th birthday on Sunday. The journalist said Friday it was based on 15 interviews with Queen Sofia, and that the Royal Palace approved the book's galley proofs before it was published, according to news agency Efe.

"What the queen said is what my book says," Urbano said.

The Royal Palace has challenged the comments attributed to the monarch, however, saying in a statement they "do not correspond exactly" with what she said. The palace also said the book also fails to reflect the queen's traditional neutrality on public affairs or respect for people who suffer discrimination, such as homosexuals.

"I do not answer to the queen or king, or the Royal Palace. I answer to the truth," Urbano told Efe.

In the book, the queen is quoted as addressing a wide range of issues and saying she opposes abortion and euthanasia. Spain allows the former under restricted circumstances, and outlaws the latter. But the queen's alleged remarks on same-sex marriage are the main source of friction and have angered gay rights groups.

Spain legalized gay marriage in 2005, becoming one of the few countries in the world to recognize same-sex couples as having the same rights as heterosexual ones, including the right to adopt children.

"If those persons want to live together, dress up as bride and groom and get married, they can do so, but that should not be called marriage because it is not," the queen is quoted as saying in Urbano's book.

Conservative newspaper El Mundo said the queen erred by breaking with her tradition of quiet neutrality.

"As human as this burst of royal sincerity might be, certainly there were better ways to make Queen Sofia's birthday a new tool for bringing society closer to the throne," it said in an editorial.