The authors of And Tango Makes Three, the controversial children’s book about a pair of gay penguins, have welcomed their first child into the world.

Justin Richardson and Peter Parnell had their baby daughter Gemma in February but the new addition to their family has only just been revealed.

Baby Gemma was born to a surrogate mother after several years of unsuccessful IVF attempts. Sperm from both men was used, although it was left to chance as to who would be the biological father.

The couple wrote And Tango Makes Three after hearing the story of Roy and Silo, two male penguins in Central Park Zoo who hatched an egg together.

The book is thought to be the most-challenged text in the past few years and libraries are asked not to stock it more than any other book.

It has been accused of being anti-family, anti-religion, unsuitable for children and pro-homosexuality.

In April, it topped an American Library Association’s (ALA) list of the book most people want banned.

However, the ALA has been keen to defend literature from censorship and celebrates Banned Books Week every autumn.