In 1971, determined young Gaye Mullins (Gauci-Marchant) launched what was to be a six-year effort to persuade the Victoria Racing Club to allow her to become a jockey.

She was staggered by the response to her first letter: "At this stage, there are no professional female jockey licences. There may be in the future."

She repeated her request, but again was left disappointed.

Finally, aged 14, she wagged school to catch the train to Melbourne to meet one of her penpals at the Victoria Racing Club, John Byrnes. She marched into his office and mounted a case for her apprenticeship.

"I said I had been riding all my life, and there was no reason why I couldn't become an apprentice," she now recalls.

Five months later, she was given a go.

The racing industry in Victoria is peppered with fine examples of strident feminism from the mid-to-late 20th century, yet few are publicly known.

For more than a century, women in the Victorian countryside had cared for and ridden horses alongside fathers and brothers at home, but were barred from riding professionally.

Amateur "ladies-only" picnic races were their only opportunity, and many recall the infamous "white line" - a gender demarcation at Australian racing clubs, abolished as late as 1982.

"It was annoying, because on these one-day events, I would hold my own against the males, so I didn't see why we weren't allowed to ride against these guys," says Debbie Waymouth, a 58-year-old jockey in Mornington.

Waymouth was granted a professional jockey's licence to race women only, in the early 1970s. She was not allowed to complete an apprenticeship.

"Men rode in the professional races and we just weren't allowed to," she said.

From the late 19th century to the early 20th century, women such as Wilhelmina Smith and June Lossius concealed their gender to race against men.

But the establishment of the Victorian Lady Jockeys' Association (1977) by first Australian female jockey Pam O'Neill and the Dame Merlyn Transition Handicap in Brisbane - a women's event at a major racecourse with professional facilities - created a landscape for professional horsewomen in the country.

By 1979, women were indentured as apprentices or licensed as jockeys, and Barbara Olive Rankin was the first woman to obtain a jockey's licence to ride against men.

New Zealand jockey Linda Jones - who was refused an apprentice jockey's licence in 1976 on the grounds that she was "too old, married and not strong enough" - became the first woman to win a race against male professional jockeys in Australia, when she rode Pay The Purple to win the Labour Day Cup at Doomben in 1979. She rode with a licence she obtained through a legal loophole in New Zealand.

Watching the race from the sideline was Pam O'Neill, who had lent Linda her saddle before the race.

"The older I get, the more I think that's typical of Australian sport, that they let somebody from another country come in but not let us do it," the 69-year-old Queenslander says.

Pam wrote letters to the Australian Racing Board for the 15 years leading up to 1979, pleading the case for female professional jockeys, with the help of Queensland racing journalist Keith Noud.

She was frustrated after years of being stopped at the gate of the Eagle Farm racecourse, where regulations forced her to hand over her horses to her trainer father.

When she was finally granted her licence in 1979 (she was 34, her husband, a lead rider in Queensland, had retired at 32), she won a treble at Southport and went back the next week to do the same.

Her losses sparked expletive-laden sexist slurs from punters, who accused her of being a "hopeless sheila".

"I would consider myself a feminist. I wasn't burning the bra, but I was fighting for what I believed in because I could see women couldn't ride and the rules needed to be broken. I believe I was put on this earth to change the racing industry," she says.

But sexism lingered like the smell of a stable dung-heap.

Trainers preferred male jockeys, and in a bid to debunk conspiracies about their physical inferiority, women sought to consistently outperform their male competitors. Many cracked under pressure, abandoning riding altogether.

"They got their licences ... but girls were only accepted in the last 10 years," Waymouth says.

By many accounts, the gender gap in horse racing in Victoria has narrowed substantially.

"The gender card, for me, doesn't get a run any more," says Australian Jockeys' Association general manager Des O'Keeffe. "There are some very good jockeys that are male, there are some fantastic ones who are female, and there are also some who are not as good."

Yes, the industry has come a long way, but can racing truly relegate the "gender card" to history?

In the past 10 years, the number of female jockeys and trainers has steadily grown, to 54 female jockeys (22 per cent of the jockey population, up from 10 per cent in 2004) and 230 licensed female trainers (23 per cent, up from 19 per cent in 2004).

Women are also among the handful of household names in the industry - take Gai Waterhouse, Clare Lindop and Michelle Payne, for instance.

This all shows improvement, but women still remain a marked minority.

Granted, there are other industry roles - strappers, farriers, vets and breeders - that are increasingly taken up by women. And if apprenticeships are a marker of future direction, this year's record female apprentice intake - six of 19 - is promising.

But many successful female jockeys and trainers acknowledge that it takes a certain type of woman, perhaps a mildly unconventional kind, to take up their line of work.

Trainer Cindy Alderson says male and female trainers are subject to the same gruelling regimen - unsociable hours, seven days a week. But the demanding schedule seems to hit women harder - particularly those with children - and it contributed to her decision to not have children.

"A couple of female trainers have noticed their partners either have to be in the business, or they don't have a partner at all," she says.

"And this seems to be more difficult for women … I think women are generally more accommodating of men who are tied down by demanding jobs."

Trainer Louise Bonella, who has two children, says balancing family and work has been challenging, but she refused to back down from it.

"It was presumed that, because I got kids, that they would become a priority instead of work. But I kept going. I had a nanny here when I was at the track each morning."

Australian Trainers' Association chief executive John Alducci says it was rarer for women to independently establish themselves as trainers and a group of father-daughter and husband-wife partnerships have proven some of the more successful players in the industry.

He says racing businesses are often a whole-of-family affair, where the business is itself a family legacy. And in many cases, women married to trainers are involved, taking care of the business' back-end.

Gauci-Marchant, now the director of non-profit Equine Goals & Dreams, estimates "90 per cent" of male trainers are helped by their partners.

"If you look at any one of the big stables, there is likely to be an even spread of females and males holding that stable up."

Indeed, of the 3249 registered Victorian stable employees in 2014, 49 per cent are female. And 41 per cent of Victorian race clubs are managed by women.

But chauvinism hasn't altogether disappeared, Alderson says.

"A while ago, most of the people who buy horses were male and tended to, or preferred, to have a male trainer, or that's something that's happened over the years, as a cultural thing. But maybe less so now," she says.

The role of gender in horse racing has come under scrutiny in recent weeks, in the wake of the race death of Caitlin Forrest, raising the Australian female jockey death toll to four in the past 15 months.

But the suggestion that these women are unusual for competing in one of the most dangerous sports is one that many resent.

And some went on the record amid the spate of deaths, announcing that they would not be deterred.

The Australian Jockeys' Association has insisted the pattern was a horrible coincidence and could not be explained by gender.

Waymouth has observed the 50-year rise of the Australian horsewoman. She has watched an apparently unchanging boundary between men and women slowly dissipate, to the extent that racing is one of the few sports where men and women can compete on a level playing field.

"If I started my career now, I would have been an apprentice. And I would have loved to have been an apprentice, and rode as a professional. It could have been."