Meet the new generation of women who refuse to use contraception.

They don’t want a baby. They don’t want an STI. But they don’t want to use contraception…

One young woman says she stopped taking contraception altogether because she “felt weird taking the pill for so long”.

Another says she doesn’t use any birth control at all because she “feels” she’s infertile — even though she’s just 23, and no doctor has told her that.

Others still claim they fear the “unnatural devices or chemicals” in some contraceptives, or that latex irritates their skin, or that the “pull-out-and-pray method” has been working just fine so far… so it must be alright.

These are not women without options. These are not women in a developing country. These are the candid online admissions of real-life women who regularly have unprotected sex.

In Australia, a staggering one-third of fertile women aged 18-44 don’t use contraception, according to one 2011 survey.* Once women actively planning a pregnancy or currently pregnant are factored in, around 17 percent of Australian women avoid birth control — despite not wanting a baby.

In other words, these women don’t want to get pregnant. But they don’t want to use contraception, either.

Related: The strangest misconceptions kids have about sex.

Given that at least 85 percent of women will fall pregnant within a year of having unprotected sex, that logic seems baffling. The oral contraceptive pill is often lauded as one of the greatest-ever advances in medical technology: why would you ignore its benefits, or at least consider other widely available options like condoms?

We asked the experts about the reasons behind the phenomenon, and the answers are equally intriguing and scary.

Why do women have unprotected sex, anyway?

“I think it’s probably a bit of everything,” Family Planning NSW Senior Medical Officer Dr Mary Stewart told Mamamia. “Obviously education and knowledge are important. We don’t have enough education around contraceptive methods.”

Reproductive Choice Australia co-president Kate Marsh agreed that some women’s failure to use birth control was down to “myths and misinformation”.

“For example, it is still widely thought that IUDs are only suitable for women who have given birth, whereas in fact anyone can use one,”  she said.

Research supports a correlation between Australian women’s lower education levels and contraceptive use. One study, for example, found 27 percent of women with less than a year-12 education avoided contraception the last time they had vaginal sex.

Related content: This form of permanent contraception is more common than you think.

Dr Stewart said women of certain age groups are also less likely to use contraception.

“Young people are obviously more likely to be spontaneous and rely on methods like withdrawal and not necessarily have a method in place,” Dr Stewart said. “And then you get to middle-aged women who are busy looking after children and sometimes parents, and don’t have a lot of time to look after their own health.”

There’s another, more surprising, reason behind some women’s backlash against hormonal contraceptives: the rise of a cultural trend toward organic “natural living”.

According to the most recent Australian Study of Health and Relationships, 14 percent of fertile women who didn’t use contraception based their decision on a perception it was “unnatural or unhealthy”.

“People are definitely more informed about what they’re putting into their body these days,” Dr Stewart said. “They’re trying to eat healthy food, and there are concerns about the effect of hormonal contraception.

Related: ‘I became a paleo nutritionist online for $29.’

Dr Stewart urged women seeking such approaches to weigh their options carefully.

“It’s important women realise there are options available to them that are not hormonal such as the copper IUD,” she said. “This is one of the methods that’s not very widely used because of a lack of knowledge.”

She also emphasised the rigorous nature of Australian regulatory bodies’ approval processes.

“I do think we need to reassure women that the hormonal methods we have are well-tested,” she said.

So what about women who rely solely on the withdrawal method to avoid pregnancy?

“Pulling out” is much more effective than leaving fertility entirely to chance, but it’s not ideal. One 2014 US study showed that 18 percent of couples using the method fell pregnant within a year. Meanwhile, the Feminist Women’s Health Centre says that figure could be as high as 27 percent, “depending on the male partner’s self-knowledge and self-control.”

Ms Marsh emphasised the method is far from failsafe.

“We know that even if a man withdraws before ejaculation there is still a risk of pregnancy,” she said.

Dr Stewart said women should be aware, too, that non-barrier methods won’t protect against STIs.

That’s frightening news, given that several common STIs are on the rise. Chlamydia rates have doubled since 2001, Australian Doctor reports, and cases of gonorrhoea have almost doubled since 2002, according to the most recent Reproductive and Sexual Health in Australia report. Research from the Kirby Institute similarly found that blood-borne viruses are at near-decade highs, and the institute’s Associate Professor David Wilson has blamed declining condom use for the worrying spike.

“Many STIs, particularly the most common ones like chlamydia, may have no symptoms or signs at all,” Dr Stewart said. “So we would often encourage women to use a barrier method as well.”

Overall, experts’ message to Australian women is clear: ditch the “fingers crossed” method and make a plan to protect yourself against STIs and unplanned pregnancy.

“I think it’s just about empowering women and their partners to be able to find a method of contraception that suits them best,” Dr Stewart said.

Ms Marsh added that while most women wanting to avoid pregnancy did already use contraception, “some of those methods are not the most effective contraception methods available”.

Related: The age to start trying for a baby if you want a large family.

We’re lucky in Australia to have world-class doctors, a solid publicly funded universal health care scheme, and freely available information about pregnancy and family planning.

So if you don’t want a baby, don’t act like you don’t need contraception.

In this day and age, there’s truly no reason to leave your fertility to chance.

Contraception fact sheets are available at the Family Planning NSW website here or reproductive resources at Reproductive Choice Australia’s website here.

* NB: Exact figures are unclear; another study placed the number of women who shunned contraception despite not wanting a family at just five percent. Dr Stewart told Mamamia she believes the true percentage is significantly higher than that.

Are you having unprotected sex? Why?

Related content:

The history of contraception is fascinating and horrifying.

‘A very different kind of abortion story .’

 2/5 women are using this (pretty risky) method of contraception.