The author of a children’s picture book chronicling the transgender journey of Jazz Jennings has urged readers to celebrate Banned Books Week this year “by picking up a book that some closed-minded person out there wanted desperately to keep out of your hands”.

America’s annual celebration of the right to read, which has been joined by authors and readers in the UK, kicked off on Sunday with a series of displays, events and readings across the US, focusing for 2016 on diverse books. According to the American Library Association, more than half of all banned books are by authors of colour, or focus on diverse communities.

“Historically, a little over half of the challenges we receive to books fall into the category of ‘diversity’ (by diverse authors or about diverse characters),” said James LaRue, director of the ALA Office for Intellectual Freedom. “Two years ago, eight of our top 10 most challenged titles were diverse. Last year, nine of them were. Four were about LGBT and transgendered youth. Three were about ‘religious viewpoint’ (mostly Islamic characters), and two were about various kinds of mental illness.”

Jessica Herthel is co-author with teenage trans girl and YouTube star Jennings of I Am Jazz, the third most challenged book of 2015. She said that when the children’s picture book was first released, its reception was “quieter than I expected”. Tracing the story of Jennings – “from the time she was two years old, Jazz knew that she had a girl’s brain in a boy’s body” – the authors at first received letters of thanks from children around the world, but the expected outrage was slow to follow.

“I’d been concerned about receiving hate mail and death threats – as Jazz’s family sometimes still does to this day – but at first there was virtually nothing. Then came the incident in Mount Horeb, Wisconsin; that’s when I knew that our message was being heard,” said Herthel.

The Wisconsin primary school, which had a transitioning pupil, told parents it would be reading the book to students, and was threatened with legal action from the Liberty Counsel. “The school panicked and agreed not to read the book – in other words, they consented to the banning of I Am Jazz,” said Herthel.

But a group of parents decided to read the book anyway in a public library, and Herthel flew from California to Wisconsin to show her support.

“I showed up at that library in the bitter cold, completely unnerved and not knowing what to expect … and even though the organising parents had set up only about 40 chairs, when all was said and done there were 600 packed into that little room,” said the author. “And when I finished reading our book aloud, the entire room applauded, and I knew at that moment that censorship is bound to fail.”

Jessica Herthel reads her book I Am Jazz at a library in Mount Horeb, Wisconsin. Photograph: Jessica Herthel

LaRue said that most of the 275 challenges to books recorded by the ALA came “from parents seeking to preserve the innocence of their children about topics such as racial conflict or sex or gender in its many manifestations”. There is some evidence to suggest that parent lobbies are becoming more protective, he added.

“But librarians would argue that the best way to guide your children’s reading is to read with them, and talk about what you read. For every parent convinced that a book is evil, there are two other parents who think it’s wonderful. So you have the right to guide your own children’s reading – but not to dictate or suppress someone else’s,” said LaRue. “The truth is, [these] issues are already a part of many children’s lives, and suppressing books about them doesn’t help anyone. In fact, these books may tell children that they are not alone, that what’s happening to them is not unique, and it can be survived. The world can be a dangerous place, but reading about it makes it less so.”

Judith Platt, director of free expression advocacy at the Association of American Publishers, agreed. “Banning books by diverse authors, or books dealing with people or situations that are unfamiliar or strange to the majority of Americans, creates fear rather than promoting understanding. Young people especially need books that shed light on a diversity of experience, background, culture, gender, and religion,” she said. “Books that feature people of colour, people with disabilities and people seeking answers to questions about gender identity create opportunities for learning and openness. This is the only way we can ever hope to stop being ‘them and us’ and become ‘we’.”

Bookshops around the US are planning events and author readings to mark Banned Books Week, which has been running since 1982. This year, for the first time in the UK, the British Library, the Free Word Centre and Islington council in London are also coming together to promote the week. Reading groups and book clubs will be promoting a list of 40 books that have been subjected to calls for censorship, from JK Rowling’s Harry Potter books to Toni Morrison’s Beloved, while the British Library is holding an evening of discussion about censorship, featuring the controversial young adult novelist Melvin Burgess.

“Islington – one-time home of George Orwell, with its rich history of radical thought, creative expression, and innovation – is the perfect place to celebrate Banned Books Week,” said Islington council’s executive member for economic development, Asima Shaikh. “I was astonished to see wonderful books like The Curious Incident of the Dog in the Night-Time and The Kite Runner on the list, and I’m proud to be a part of this celebration. Our libraries should be places that encourage the collision of ideas and the challenge of opinions and which open up, not close off, doors to new worlds of knowledge, experience, and adventure.”

Herthel said that people had tried to censor books “probably for as long as books have been around”. Books to receive challenges in recent years include To Kill a Mockingbird and The Great Gatsby, with the Bible featuring on 2015’s list of most-challenged books.

But the author, who is also director of the Stonewall National Education Project, was clear that “with the rise of Donald Trump and the wave of xenophobia, racism, misogyny, and Islamophobia that has accompanied his campaign, the sharing of stories has never been more crucial”.

“Without the authentic stories of immigrants, women, LGBT people, Muslims, etc, people will become more entrenched in their view of those groups as the Other. What we need now is more information, more voices, and more speech. Otherwise, perception becomes reality, and the diversity that has long been one of America’s greatest strengths will end up tearing this country apart. I urge everyone to celebrate Banned Books Week by picking up a book that some closed-minded person out there wanted desperately to keep out of your hands,” Herthel said.