Trans woman Sarah says it is her gender identity not her physicality that makes her a woman. Credit:Steven Siewert "I was just as much a woman when I was 12 years old going to North Sydney Boys High School and doing a very good job of pretending to be one of the boys." But for some this is not enough. They argue Sarah has not earned the right to the title "woman". Welcome to a new and complex chapter of the gender wars. As more trans women find the courage to come out they are facing a sisterhood that is not as willing to embrace them as they might have hoped.

Some feminists feel the push for transgender acceptance comes at the expense of everything the women's movement has fought for. Last week, American actress Rose McGowan launched a blistering attack on the world's most famous trans woman – former Olympic athlete Caitlyn Jenner – who was this month named one of Glamour Magazine's Women of the Year. "You're a woman now? Well, f---ing learn that we have had a VERY different experience than your life of male privilege," McGowan said in a Facebook post she later deleted after facing accusations of transphobia. "Being a woman comes with a lot of baggage. The weight of unequal history. You'd do well to learn it. You'd do well to wake up. Woman of the year? Not by a long f---ing shot."

Like many women, The Charmed star was frustrated by Jenner's assertion that "the hardest thing about being a woman is figuring out what to wear", arguing she was perpetuating harmful gender stereotypes. Some have gone further, claiming people who have benefited from male privilege and have not endured menstruation; the threat of rape; sexual harassment and the gender pay gap should not get to define womanhood. On Thursday, under high security, feminist icon Germaine Greer defied a petition signed by thousands to stop her delivering a lecture at Cardiff University on the grounds that her views were transphobic. She had previously claimed trans women were not "real women", later inflaming the debate by adding, "Just because you lop off your dick and then wear a dress doesn't make you a f---ing woman."

She told the Cardiff audience: "If you didn't find your pants full of blood when you were 13 there's something important about being a woman you don't know." Former University of Melbourne feminist academic Sheila Jeffreys has expressed similar views. Both women have received death threats. But is it hate speech against a persecuted minority? Or a difficult but important conversation our increasingly gender-diverse community needs to have? Leaders in the modern feminist movement have distanced themselves from Greer and Jeffreys, saying their opinions are outdated and bigoted and that third-wave feminism welcomes all women. "Including trans women might make you feel uncomfortable but Jews made Australians feel uncomfortable, Vietnamese people made Australians feel uncomfortable. Discomfort makes for a stronger community," Jenna Price, co-founder of feminist movement Destroy the Joint, said.

Yet even that acceptance comes with a caveat. Price insists trans women must accept that reproductive rights are central to what it means to be a woman. This is where some of the friction lies. Is gender determined simply by the way we feel, regardless of the biological characteristics we were born with? Lauren Rosewarne, a senior lecturer in feminism, gender and sexuality at the University of Melbourne, said that while she disagrees with the radical feminist position on trans women, we should not be scared to ask questions. "We should be able to discuss these issues in a non-hostile environment, where people don't have to feel like they are going to be attacked for being sexist or transphobic or homophobic simply because they are struggling to understand what is, for many people, a 'new' issue. This isn't how a society evolves." Germaine Greer caused controversy by arguing trans women are "not real women".

But there are concerns that in the clamour to be inclusive women are once again being silenced and their bodies policed. "You can't speak publicly any more at events about women's experiences that trans women don't have – having vaginas, abortion, menstruating – because that alienates trans people," said one woman in her 20s who works for a prominent women's welfare service in Melbourne. She told The Sunday Age that many younger feminists like her were reluctant to speak out because the backlash is "terrifying". "The fact that women have vaginas means something for our safety, for our health and hygiene, it means something for our sexuality. The experiences of the majority of women are being sidelined, which is really problematic because that's real misogyny when women can't speak of their own experiences any more." However, trans advocates say that excluding trans women increases the risk of persecution against a minority who are already the target of abuse and violence, partly driven by the misperception that they are impostors.

They argue it is the same dangerous rhetoric once used to deny the existence of gay and lesbian people. "It's really frightening and disenfranchising because I'm a proud feminist and these are women that I would have liked to have been able to look up to but suddenly it feels like I've been thrown under the bus," said Margot Fink, a 21-year-old Melbourne trans woman, who was last month nominated for Young Australian of the Year for her advocacy with LGBTI youth group Minus 18. "It feels like I've been thrown under the bus." Margot Fink, (left) on radical feminists who say trans women are not "real" women. Credit:Paul Jeffers "When I was struggling to come out I thought I was a freak. I felt very isolated and a lot of shame. So when people say these things they reinforce that feeling not only in trans people but in the people around them and they create a very unsafe environment for people to be themselves." Caitlyn Jenner's rise to international stardom as the unappointed spokesperson for the trans community has done little to ease tensions.

While the former star of reality TV show Keeping Up With The Kardashians has been a boon for transgender visibility and acceptance, she has caused discomfort among feminists and trans activists alike with the way she has chosen to express her femininity. In June she came out to the world in a highly sexualised image on the cover of Vanity Fair, and in a television interview stated, "My brain is much more female than male", angering feminists who said it was this type of reasoning that had been used to keep women in positions of inferiority for centuries. Her recent comments on women's fashion struggles only increased the criticism.

A fierce debate erupted on Destroy the Joint's Facebook page, with many labelling Jenner's comments "patriarchal", "misogynistic" and "patronising" while others railed at her critics for their transphobia. Sarah, who started taking hormones two years ago, said Jenner's views and experiences were not representative of most trans women, who faced daily challenges the Hollywood celebrity could not comprehend. And while acknowledging she has benefited from male privilege, Sarah says it has not meant her life has been easy. "It's offset in some ways by an incredible degree of persecution and internalising negative messages from society about us as trans people. The privilege stops when you stop presenting as a man," she said.

Having worked in industrial relations for 10 years, she has noticed her male colleagues who once treated her as an equal now talk over her in meetings. "It's little things like going to get your car serviced and the guy treating you like an idiot. Or I used to walk around at midnight by myself and I never felt unsafe on the streets. Now I'm hyper aware of parking in a basement car park or walking past a bar where drunk people are coming out." Karen Pickering, a feminist activist and founding member of SlutWalk in Australia, said gender identity was complex terrain and to reduce it to policing boundaries and asserting one identity as superior to another was similar to patriarchy. Trans woman, Sarah 12th November 2015 Photo: Steven Siewert Credit:Steven Siewert "It not only drains energy and time away from the real struggles like equal pay and violence against women but it keeps feminists in a cycle of lateral violence against each other."

Carolyn D'Cruz, convener of the gender, sexuality and diversity studies program at La Trobe University, said the debate must shift from "what makes a woman", to challenging the rigid binary system of male and female gender classification. "Are two categories enough? That has been asked all over the world and some countries actually now have more than two genders. It's time we recognised there's a lot more variants in the way people perform their genders in everyday life." jstark@fairfaxmedia.com.au Follow Jill on Twitter