A Labour frontbencher has broken ranks in the discussion over trans rights and declared that "men have penises, women have vaginas".
Characterising his comments as a "biology lesson", Wes Streeting, the shadow health secretary said he however believed trans rights should be debated in a "respectful" way.
It comes after Keir Starmer and his deputy Angela Rayner both rejected the framing of the question about genitalia – which broadcasters have taken to asking politicians.
MPs touring the studios in recent weeks have been subjected to questioning over whether they believe someone with a penis can identify as a woman.
Appearing on TalkRadio with host Julia Hartley-Brewer, Mr Steeting replied: "Men have penises, women have vaginas, here ends my biology lesson."
He added: "That doesn't mean by the way that there aren't people who transition to other genders because they experience gender dysphoria and we should acknowledge that and conduct the debate in a respectful way that respects those people's rights and dignity."
His comments come on the morning Jamie Wallis, a Conservative, came out as the first trans member of parliament.
Mr Streeting's reply prompted delight from radio host Ms Hartley-Brewer, who started clapping and replied: "Wes Streeting, can I just say, I've got a Labour MP on who can answer that question and who did biology."
The MP added: "Oh god, I'm getting a clap from Julia Hartley-Brewer, this is the end of my lefty street-cred, if I ever had any."
His response to the question contrasts with the approach taken by the Labour party leadership – which has said the framing is unhelpful and upsetting.
Asked the same question on Monday Keir Starmer told LBC radio: "I don't think that discussing this issue in this way helps anyone in the long run.
"What I want to see is a reform of the law as it is, but I am also an advocate of safe spaces for women.
"I want to have a discussion with anybody who genuinely wants to find a way through this.
"I do find that too many people retreat to or hold a position which is intolerant of others. And that's not picking on any individual at all, but I don't like intolerance, I like open discussion."
And deputy leader Angela Rayner had previously replied that the framing of the question "really debases the serious issues that people face" and "really upsets me".
“When we debase it to what genitalia you’ve got, I think all that does is damage people and it doesn’t help us go forward on some of the real issues that people are facing," she said.
Mr Streeting, asked by Ms Hartley-Brewer whether he could "have a word with Keir Starmer", said: "He doesn't need any advice from me ... we want a respectful debate about these issues and we recognise that there've been tensions on the gender identity debate and sex-based rights debate and we've just got to acknowledge that and find a way through that maybe not everyone loves but maybe everyone can live with."