Harry Potter star Daniel Radcliffe has waded into the transgender row involving author JK Rowling and said he hopes her comments will not "taint" the series for fans.
Rowling attracted criticism for tweets posted over the weekend.
She took issue with a headline on an online article discussing "people who menstruate," and said: "I'm sure there used to be a word for those people. Someone help me out. Wumben? Wimpund? Woomud?"
Critics accused her of being transphobic, an allegation Rowling strongly denies.
Actor Radcliffe, who became a worldwide star after playing schoolboy wizard Harry in the blockbuster adaptations of the beloved book series, has now commented on the controversy, stating "transgender women are women".
He shared a statement through the LGBT suicide prevention charity The Trevor Project, saying that while Rowling "is unquestionably responsible for the course my life has taken... as a human being, I feel compelled to say something at this moment".
The stars from left to right; Rupert Grint, Daniel Radcliffe and Emma Watson with the author J K Rowling arrive for world premiere of 'Harry Potter and the Philosopher's Stone at the Odeon Leicester Square in London.
Harry Potter author J.K Rowling signs a fans shirt at the Waterstone`s book shop in Edinburgh as she launches her new book Harry Potter and the Order of the Phoenix.
Author, Joanne Kathleen Rowling, 34, (J K Rowling) at Kings Cross Station London at the launch of her new Harry Potter book, 'Harry Potter and the Goblet of Fire'. The fourth book, in series of seven which have now combined sold more than 35 million copies. * The Goblet of Fire has achieved advanced sales of two million. 25/11/2000: JK Rowling's latest Harry Potter offering has been pipped to a children's book prize by a re-telling of the classic A Pilgrim's Progress. Geraldine McCaughrean's version of John Bunyan's work scooped the first ever Blue Peter Book Of The Year Award. * 16/02/2001 dated 8/7/00 of Harry Potter author Joanne Kathleen Rowling. Teenage wizard Harry Potter has enchanted library users by sweeping to the top of the lending league for children's books, figures showed Friday February 16, 2001. JK Rowling's best-selling creation took the first three places for kids' books in the annual round-up of reads with Harry Potter and The Philospher's Stone at number one.
Author JK Rowling (2nd right) with director alfonso Cuaron and the stars from left to right, Rupert Grint, Emma Watson and Daniel Radcliffe at the UK premiere of Harry Potter And The Prisoner of Azkaban at the Odeon Leicester Square in Central London, the third film from author JK Rowling's series of books on the boy wizard.
Whitney Stanbra, 6, from Basingstoke poses with a 'Platform 9 and 3/4' sign beside a special WAGN Harry Potter train arrives on Platform 9 at King's Cross station in London before beginning its first ever passenger journey from London King's Cross to Cambridge. * King's Cross station plays a leading role in the film 'Harry Potter and the Philosopher's Stone' which is released at cinemas across the country.
A special WAGN Harry Potter train arrives on Platform 9 at King's Cross station in London before beginning its first ever passenger journey from London King's Cross to Cambridge. King's Cross station plays a leading role in the film 'Harry Potter and the Philosopher's Stone'. * ... which is released at cinemas across the country.
Actors Robbie Coltrane (rear), and (from left) Rupert Grint Emma Watson and Warwick Davis at Kingscross Station, central London, for the Harry Potter & The Philosopher's Stone - DVD & video launch party.
Stars from the latest Harry Potter film 'Harry Potter and the Chamber of Secrets' (from left) Emma Watson, Daniel Radcliffe and Rupert Grint, during a photocall at the Guildhall, London, to promote the new film.
Daniel Radcliffe, who plays Harry Potter (left) with the characters creator JK Rowling (centre) and co-star Emma Watson as they arrive for the celebrity film premiere of Harry Potter and the Chamber of Secrets at the Odeon Leicester Square, London.
The cast, crew and author arrive for the celebrity film premiere of Harry Potter and the Chamber of Secrets at the Odeon Leicester Square in London's West End.
The stars of Harry Potter and the Chamber of Secrets, from left to right; Rupert Grint, Daniel Radcliffe and Emma Watson during the worldwide launch of the DVD/VHS at Leavesden Studios in north London.
The cast and crew of Harry Potter and the Chamber of Secrets during the worldwide launch of the DVD/VHS at Leavesden Studios in north London.
Five girls head the queue outside Waterstones in Piccadilly, London for the eagerly awaited fifth installment of Harry Potter. The girls (from left) Suzanna Dickson, Stevie Finegan, Savannah Mazda, Vienna Francis-Mullins and Sinead Miller, * .. all from London, have been waiting for nearly eight hours to ensure they get a copy of Harry Potter and The Order of the Phoenix. harrypottergal
The stars, from left to right; Daniel Radcliffe, Emma Watson and Rupert Grint pose for photographers during a photocall to promote the new Harry Potter movie 'Harry Potter and the Prisoner of Azkaban' at The Gladstone Library in central London.
MTV presenter Dave Berry (left) with Harry Potter stars Daniel Radcliffe, Rupert Grint and Emma Watson during their guest appearance on MTV TRL UK at the MTV Studios's in Camden.
Star of the film Daniel Radcliffe arrives for the UK premiere of Harry Potter And The Prisoner of Azkaban at the Odeon Leicester Square in Central London, the third film from author JK Rowling's series of books on the boy wizard.
Author JK Rowling (centre right) and stars of the film Daniel Radcliffe (left), Rupert Grint and Emma Watson arrive for the UK premiere of Harry Potter And The Prisoner of Azkaban at the Odeon Leicester Square in Central London, the third film from author JK Rowling's series of books on the boy wizard.
(From left to right) Rupert Grint (Ron), Emma Watson (Hermione), and Daniel Radcliffe (Harry) arrive for the Global DVD & VHS Launch party of Harry Potter And The Prisoner Of Azkaban, at Middle Temple in central London
JK Rowling arrives at Edinburgh Castle for the Launch party for her latest Harry Potter Book, Harry Potter and the Half-Blood Prince.
Jennifer Ellison, Hagrid and Professor Dumbledore during a visit to hand out copies of the new Harry Potter book, which was released at midnight.
Fans brave the rain outside the Odeon cinema in London's Leicester Square in anticipation of the arrivals for the world premiere of the new film 'Harry Potter and the Goblet of Fire', Sunday November 6, 2005. See PA story SHOWBIZ Potter. PRESS ASSOCIATION photo. Photo credit should read: Yui Mok/PA.
The Harry Potter films win the Empire Outstanding Contribution Award at the Sony Ericsson Empire Film Awards 2006, from the Hilton London Metropole, central London, Monday 13 March 2006. See PA story SHOWBIZ Empire. PRESS ASSOCIATION Photo. Photo credit should read: Ian West/PA
The cast of Harry Potter And The Order Of The Phoenix, (left to right) Rupert Grint, Emma Watson, and Daniel Radcliffe, on the Thames Terrace of County Hall in south London, ahead of the European premiere of the film next week.
Emma Watson arrives for the UK Premiere of Harry Potter And The Order Of The Phoenix at the Odeon Leicester Square, central London.
Emma Watson arriving at the European Premiere of Harry Potter and the Order of the Phoenix, Odeon Cinema, Leicester Square, London.
JK Rowling at the launch of Harry Potter and the Deathly Hallows at The Natural History Museum in London
The cast of Harry Potter receive the award for Best Family Film for Harry Potter and the Order of the Phoenix during The National Movie Awards at the Royal Festival Hall, central London.
(from left to right) Tom Felton, Emma Watson, Rupert Grint, Daniel Radcliffe, Bonnie Wright and Jessie Cave are seen at a photocall to launch the new film, Harry Potter and the Half-Blood Prince, at Claridges Hotel in central London.
Rupert Grint (left), Emma Watson and Daniel Radcliffe (right) arriving for the world premiere of Harry Potter and the Half-Blood Prince at the Odeon Leicester Square, London.
Rupert Grint, Emma Watson and Daniel Radcliffe arrive for the world premiere of Harry Potter and the Half-Blood Prince at the Odeon Leicester Square, London.
(left to right) Daniel Radcliffe, Emma Watson, JK Rowling and Rupert Grint arriving for the World Premiere of Harry Potter and The Deathly Hallows : Part One, at the Odeon West End, Leicester Square, London.
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Writing that the issue is not about "in-fighting between JK Rowling and myself," Radcliffe said: "Transgender women are women. Any statement to the contrary erases the identity and dignity of transgender people and goes against all advice given by professional health care associations who have far more expertise on this subject matter than either Jo or I."
The 30-year-old then cited statistics from The Trevor Project, claiming 78% of transgender and non-binary youth reported being the subject of discrimination due to their gender identity.
He said: "It's clear that we need to do more to support transgender and non-binary people, not invalidate their identities, and not cause further harm."
And Radcliffe addressed fans on social media who said they could no longer enjoy the Harry Potter series due to their disagreement with Rowling.
"To all the people who now feel that their experience of the books has been tarnished or diminished, I am deeply sorry for the pain these comments have caused you," he said.
"I really hope that you don't entirely lose what was valuable in these stories to you. If these books taught you that love is the strongest force in the universe, capable of overcoming anything; if they taught you that strength is found in diversity, and that dogmatic ideas of pureness lead to the oppression of vulnerable groups; if you believe that a particular character is trans, non-binary, or gender fluid, or that they are gay or bisexual; if you found anything in these stories that resonated with you and helped you at any time in your life — then that is between you and the book that you read, and it is sacred.
"And in my opinion nobody can touch that. It means to you what it means to you and I hope that these comments will not taint that too much."
Following a backlash, Rowling, 54, stood by her comments, arguing "it isn't hate to speak the truth".
She tweeted: "If sex isn't real, there's no same-sex attraction. If sex isn't real, the lived reality of women globally is erased. I know and love trans people, but erasing the concept of sex removes the ability of many to meaningfully discuss their lives. It isn't hate to speak the truth."
It is not the first time Rowling has been accused of being transphobic. In December she voiced her support for a researcher who was sacked after tweeting that transgender people cannot change their biological sex.