Daniel Radcliffe hopes JK Rowling's comments about gender will not "taint" the Harry Potter series for fans.

In a statement posted on an LGBT suicide prevention charity website, the actor said: "Transgender women are women.

"Any statement to the contrary erases the identity and dignity of transgender people."

JK Rowling had been criticised for tweets taking issue with the phrase "people who menstruate".

Radcliffe said this was not about "in-fighting" and added he felt "compelled to say something" because Rowling was responsible for the "course his life has taken".

'Love is the strongest force'

Writing on The Trevor Project's website he said he was sorry to anyone whose "experience of the [Harry Potter] books has been tarnished".

"If these books taught you that love is the strongest force in the universe... 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.

"I hope that these comments will not taint that too much."

The actor started supporting the charity, which provides suicide-prevention counselling to young people in the US, in 2009.

Rowling had tweeted at the weekend about an article discussing "people who menstruate".

"I'm sure there used to be a word for those people. Someone help me out. Wumben? Wimpund? Woomud?"

In response, she was called transphobic.

Rowling stood by her comments, saying it "isn't hate to speak the truth".

"My life has been shaped by being female. I do not believe it's hateful to say so.

"I know and love trans people, but erasing the concept of sex removes the ability of many to meaningfully discuss their lives."

'Identity and dignity'

Radcliffe said it's important not to "invalidate" transgender people's identities and "cause further harm".

"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 actress who played character Cho Chang in the Harry Potter films, Katie Leung, also shared support for trans people.

Conversation online had touched on the representation of black, Asian and minority ethnic characters in the Harry Potter series, with Cho Chang trending on Twitter.

Leung tweeted: "So, you want my thoughts on Cho Chang? Okay, here goes..."

Instead of commenting, she used the rest of the thread to share links to charities helping black trans people.

Rowling was criticised in December last year for defending a woman who lost her job after saying children cannot change their biological sex.

At Maya Forstater's employment tribunal, which she lost, the judge spoke about the "enormous pain that can be caused by misgendering".

JK Rowling used the hashtag #IStandWithMaya, and said women shouldn't be "forced" out of jobs for "stating that sex is real".