Comedian Eddie Izzard has hit out at Ian McEwan, calling the novelist's comments about transgender people "a bit weird".
As the increasingly bitter argument over whether gender is something people can define for themselves continues, Mr McEwan recently told an audience: "Call me old-fashioned, but I tend to think of people with penises as men."
In a speech to the Royal Institution, he said: "Some men in full possession of a penis are now identifying as women and demanding entry to women-only colleges, and the right to change in women’s dressing rooms ...
"The self, like a consumer desirable, may be plucked from the shelves of a personal identity supermarket, a ready-to-wear little black number."
Izzard, who describes himself as "a straight transvestite or a male lesbian", told ITV's The Agenda on Monday that he would "fight" anyone who queried his own gender identity.
He said: "I could go on and on about it but I just think he's wrong. He said it was 'off the shelf'. People are taking things 'off the shelf'.
"If he was transgender he might look at it a bit differently. But it's a bit weird for him - he's obviously great at what he does - but to just look over there and say people are pulling things off the shelf.
"I didn't pull it off the shelf. I knew when I was four and I came out when I was 23. That was 31 years ago. Surely we have moved on again from that point. That's so backward looking. It just seems like the 60s never happened to him.
He added: "We get obsessed about it [labelling]. What do you add to society, what you do in the world, that's what should be important.
"Transgender has always been the poor relation in the LGBT community and it's interesting that writers are coming out and bashing us now.
"But I've been out for 31 years now and if anyone has a problem with it I'll fight them."
McEwan's comments followed a protracted row over feminist author and campaigner Germaine Greer claim that transgender men could not be women.
She was faced a fierce campaign to prevent her delivering a lecture at Cardiff University.
"I don’t believe a woman is a man without a cock. You can beat me over the head with a baseball bat. It still won’t make me change my mind," she said during the talk."
Shadow Education secretary Lucy Powell told The Agenda she would like to see education on transgender issues "as part of a PSHE curriculum - everything from sexting to internet safety and radicalisation but also absolutely about LGBT issues."
She added: "As Eddie says the T in LGBT - trans - is often the poor relation and is probably 30 to 40 years behind our understanding of gay rights."
In a statement, Mr McEwan said he was "surprised" his remarks had caused controversy and said it was "biologically unexceptional" to state that having a penis was "inalienably connected to maleness".
He wrote: "However, biology is not always destiny. That the transgender community should want or need to abandon their birth gender or radically redefine it is their right, which should be respected and celebrated. It adds to the richness and diversity of life.
"It's an extension of freedom and the possibilities of selfhood. Everyone should deplore the discrimination that transgender communities have suffered around the world.
"That the community should sometimes find itself in conflict with feminists (over changing rooms, beauty pageants, access to women's colleges) -- well, that's a conversation on which I can shed no useful light."