She's a wowser. A no-nonsense political crusader beloved by both teenage girls and their mothers. A religious conservative in feminist clothing. A brazen careerist. A gifted networker and generous mentor.

The Canberra-based activist, mother of four and author of four books is difficult to pigeonhole and impossible to ignore. Friend and collaborator Julie Gale, founder of the advocacy group Kids Free 2B Kids, describes her as "one of the most misunderstood women in the public arena".

Melinda Tankard Reist grew up in rural Victoria, the eldest of four daughters. Her parents were farmers – "Good country people who have no idea how they produced me," she jokes.

Young Melinda loved motorbikes and horses, but she was also drawn to words. She began her career as a journalist, contributing to the Melbourne Herald's racing guide and working as a regional-newspaper cadet before turning her hand to opinion and feature writing in the late 1980s, after a stint in the United States. "I had started to realise that my opinions were quite strong and maybe I wasn't suited to life as a daily reporter," she recalls.

One topic on which she had particularly strong opinions was abortion. Tankard Reist is a self-described "pro-life feminist", and it was the intersection of these two identities that formed the focus of much of her early writing and activism. But it was only when she started writing about the sexualisation of children in the late 2000s that Tankard Reist became the name she is today. Picking up where debates around young women and raunch culture left off, she gave voice to parents' fears about the impact that sexual imagery and popular culture were having on their kids.

Says Tankard Reist, "I think people had been feeling an unease about the issue, but hadn't been able to join all the dots. When Getting Real [the 2009 anti-sexualisation anthology edited by Tankard Reist] came out, people were able to name the disease they felt: the pornification of culture, little girls being too sexy too soon, children being pressured to look and act much older than they actually were."

Now Tankard Reist is taking on the global pornography industry with her new anthology, Big Porn Inc. The book presents a collection of 40 essays covering everything from strip clubs to sexting to the role pornography plays in shaping the advice proffered by sex therapists. But most of the contributions can be boiled down to one of two concerns: that pornography that uses violence, abuse and exploitation has become increasingly mainstream; and that the ubiquity of porn on the internet is perverting our experience of sexuality.

"My biggest concern is the effect of pornography on young people and children," says Tankard Reist. "We are socialising boys into a very brutalised version of masculinity. Boys are often looking at porn before they become sexually active, and they're seeing very callous images of women. What we are allowing to happen to the sexuality of our young people is diabolical."

She recalls one 15-year-old boy she interviewed who told her he looked to porn as a way to figure out how sex works. When he'd tried to act out what he had seen online in real life, he was surprised to discover that girls didn't like it. "Here we have a teenage boy who is using pornography as a sexual handbook. What hope is there for his natural sexuality to develop when he has been trained in hard-core misogyny?"

Certainly, the sexual culture presented in Big Porn Inc is bleak. One chapter details a Japanese computer game (banned in Australia, thanks to a campaign led by Tankard Reist) that asks players to simulate the sexual assault of a mother and her two daughters. Another describes the trivialisation of incest in online pornography. A Scottish woman recalls the betrayal she felt upon discovering her husband was a regular porn user; a young American the horror of knowing that images of her childhood rape at the hands of her uncle are circulating online.

At the Sydney launch in October, Tankard Reist described the book as "the hardest gig of [her] life". Her co-editor, Abigail Bray, broke down in tears part-way through her own presentation, describing the abusive and degrading material she had encountered as part of her research for the book – much of it literally a 20-second Google search away. But evidence of the impact this content is having on our collective sexuality – and on our psyches more generally – is thinner on the ground.

Tankard Reist links media reports of increased child-on-child sexual assault to "children acting out what they're learning from pornography", but the 2010 Australian Crime Commission study on which the stories were based stresses that "sexualised behaviour in children is only rarely a result" of sexualised media. The American Psychological Association's 2007 investigation into the sexualisation of girls is more concerned with narrow beauty standards than it is with sexual media content.

"There is often a suggestion in the anti-porn movement that men's attitudes towards women's sexuality were better in the 'good old days'," argues Alan McKee, a professor in film and television at the Queensland University of Technology and co-author of The Porn Report. "But we know statistically that young men today have far better attitudes towards women than their fathers or their grandfathers did.

"There is some awful stuff online," McKee admits. "But there is a big difference between what you can find if you look for it and what people are actually choosing to look at. If you look at the most popular [pornography] websites, the top five are all amateur sites, where people post home-made videos of themselves having sex."

But for Tankard Reist, the distinction between these and the abusive material detailed in Big Porn Inc is only one of degree. All pornography entails treating another human being as an object for sexual gratification, she argues; therefore all porn is degrading. "I don't believe [that there is a safe degree of pornography]," she told the ABC's One Plus One in November. "I think that any level of depiction of women as subordinate, as second class, as purely for sexual pleasure, as service stations for men and boys, is dangerous."

This kind of unwavering conviction is one reason for Tankard Reist's success as an activist. A scroll through her Twitter feed reveals a woman of dogged determination, who will pursue her targets – be they radio shock jock Kyle Sandilands, retailer Kmart or US pop star Kanye West – relentlessly.

It is a message that has attracted a wide range of fans and collaborators, from teenagers to teachers to psychologists such as Steve Biddulph and Michael Carr-Gregg. "It's very difficult to debate with her, because if you're talking to a mainstream audience you sound like a boring dick," observes one commentator who is regularly pitted against Tankard Reist. "She argues anecdotally, she argues emotively, and she is highly effective at it."

She is also a master at coalition building. Tankard Reist doesn't just use Twitter to proselytise and campaign – her feed is a rapidly updated collection of back-and-forths with supporters, snippets from her personal life, and promotion of other people's work. "The first time we met for a coffee, we were still talking five or six hours later," says media blogger Erica Bartle. But Tankard Reist's campaigning style has also attracted enemies. "Some days I don't want to turn on my computer," she says.

It is not just Tankard Reist who is on the receiving end of their vitriol: it extends to anyone associated with her. Several Tankard Reist associates Sunday Life contacted for this story later retracted their interviews, afraid of the personal and professional fallout. Others would speak only on the condition of anonymity.

Nor is the criticism directed at her just an extension of the misogyny she rails against in her work. Tankard Reist's brand of feminism may be media-friendly, but it is also a feminism that makes many people uncomfortable. Much of that discomfort goes back to her identification as a "pro-life feminist". Tankard believes that abortion is a form of "violence against women", one that many find traumatic and laden with regret.

"Abortion is often an excuse not to deal with the structural conditions that compel women to have abortions," she told One Plus One. She draws the line at government regulation, she says, preferring to focus "on those women who would rather not choose abortion. What can we do to make it easier for women who would prefer to make another choice?" (In the '90s, she co-founded Karinya House, an organisation providing support for pregnant women "in crisis".)

But Melbourne-based ethicist and regular sparring partner Leslie Cannold is sceptical. "To get the wide reach she does, she is absolutely dependent on us not knowing the full extent of what she's done in the past," says Cannold.

Tankard Reist worked as a media and bioethics adviser for former Tasmanian senator Brian Harradine for 12 years, during which time he successfully blocked and continued to campaign against the abortion drug RU486. She also personally opposed changes to legislation that would have required pro-life pregnancy-counselling services to disclose their affiliations in their advertising.

For others, the discomfort is more philosophical. As high-profile second-waver Eva Cox puts it, it's about the difference between "a view of feminism in which choices and opportunities are not determined by gender" (a group in which Cox includes herself) and "one that wants to protect women, whether it be from men, from sexuality or something else" – the world view Cox suspects Tankard Reist subscribes to.

However, as UNSW historian Zora Simic observed in a recent speech to the European Conference on Politics and Gender, Tankard Reist is now one of Australia's best-known feminist voices. And whether you agree with her or not, it is her language – and that of her supporters – that increasingly frames our debates on sex, gender and popular culture.

CONSERVATIVE FEMINISM

Melinda Tankard Reist isn't the only high-profile woman redefining feminism ... and making enemies in the process. In a speech in 2010, former Republican vice-presidential candidate Sarah Palin rallied the "pro-woman sisterhood" and spoke of an "emerging conservative feminist identity".

Like Tankard Reist, Palin is pro-life, which immediately disqualified her from being a feminist according to many – among them When Harry Met Sally screenwriter Nora Ephron. "You can't call yourself a feminist if you don't believe in the right to abortion," Ephron wrote, while blogger Amanda Marcotte dismissed Palin as "just the latest incarnation of a long and noble line of feminist anti-feminists". LA Times columnist Meghan Daum was less cynical, writing, "If [Palin] has the guts to call herself a feminist, then she's entitled to be accepted as one."

To date, this is one arena in which Palin's fellow Republican Michele Bachmann is yet to follow her lead, but evidence suggests that Palin-style feminism is catching on Stateside. Conservative women's group Smart Girl Politics, born from the blog of the same name, boasts 55,000 members and hosts an annual activist training summit.

"I was at a debate recently where a lot of people were saying we needed to reinvent feminism because it has become loaded with too much negativity," says Eva Cox. "But if it's negative, it is interesting that the right is picking it up."

Still, Cox warns, "Those who don't want feminism to be co-opted by the Palins and the Tankard Reists need to do some thinking about what direction they want to take it in instead."

For Tankard Reist's part, she says she's not interested in labels – she just wants people to engage with the substance of what she has to say. "Call me whatever the hell you want, I don't care," she says. "I believe my work is pro-woman, pro-girl. Just let me get on with it."

From: Sunday Life