While I was catching up with a female friend recently, she mentioned a one-night stand during which her partner hadn’t used a condom. “It’s fine,” she said, when I opened my mouth. “I’m on the pill.”

The thought of sexually transmitted infections (STIs) never crossed her mind. Cases of STIs, such as chlamydia, are on the rise – with under-25s most at risk.

So why are young women playing Russian roulette with their sexual health?

No one can deny that the pill is invaluable for preventing unwanted pregnancy, and that it affords women greater sexual agency.

“Nowadays, it seems like the pill is an integral part of many women’s routine,” says Francesca Wright, 19, president of the University of Exeter’s feminist society. “It gives them a large amount of independence that they wouldn’t otherwise have.”

But the downside is that the pill seems to have made women complacent about their sexual health, especially in a student environment, where casual sex is quite common.

Young women are very concerned about preventing unwanted pregnancy. On the social media app Yik Yak, a post that trended in my university town joked about the number of girls asking for the morning-after pill following a popular night out.

“But I think there is a very blasé attitude towards sexual health and STIs,” says Katie Pryer, 20, a student at the University of Warwick. “There’s very much an ‘oh, it’ll never happen to me’ frame of mind.”

I can relate. If you’re on the pill, the assumption that your sexual partner is “clean” is all too tempting in the heat of the moment. It’s one that, over a year ago, led me to take a chlamydia test at local clinic in a frenzy of – thankfully, unfounded – paranoia.

Recently, I watched a decades-old grainy video of Winona Ryder discussing the biggest sexually transmitted problem of all, Aids. “There’s this big rumour that guys don’t like to wear condoms, so it doesn’t come up, and you end up risking your life,” she says.

I never expected to be taking sex advice from the 90s pin-up and Beetlejuice star, but I’m struck by how relevant Ryder’s words are so many years later. Six thousand people in the UK were diagnosed HIV-positive in 2013 (pdf).

A friend of mine – who wishes to remain anonymous – says she feels reluctant to ask a sexual partner to wear a condom because it can “spoil the moment” and “feel less good for the guy”.

This is incredibly dangerous. The NHS reports that young people aged 16-24 account for around 63% of chlamydia cases nationally. Also known as “the silent disease”, chlamydia causes no obvious symptoms – 80% of people carrying it don’t know they have it. It’s particularly dangerous for women, and can cause infertility.

Gonorrhoea, or “the clap”, can be similarly silent – with around half of women not experiencing any symptoms, and can also lead to infertility if left untreated.

Genital herpes is particularly common in people aged 20-24, and while it’s easily treated, they are few symptoms and, if undetected, it can cause problems during pregnancy.

“Many young people feel that they are not susceptible to STIs while on the pill,” says Kate Reeder, a practice nurse from York who specialises in sexual health. She recommends using other forms of contraception as well, such as condoms, to prevent the spread of STIs.

Neither is the pill 100% effective at preventing pregnancy. “I was on antibiotics, and my GP told me that this meant the effectiveness of certain pills is reduced,” says Ellie Foster-Lill, 20, a student at Royal Holloway, University of London. “So condoms are a must.”

The morning-after pill, of course, is intended only as an emergency option. Used too often, it can cause nausea and heavier, more painful periods. And it still doesn’t combat STIs.

“It’s important that students are made aware of the sexual health support available to them,” says Kate Hawkins, vice president for welfare and diversity at the University of Exeter.

Hawkins cites Exeter-based student groups such as Shag (Sexual Health Awareness Group), which give out condoms to students. Student health centres across the country also offer free sexual health advice.

The statistics are clear – we can’t keep blindly assuming that every new sexual partner is clean. Even if they assure you they’re STI-free, they may be unaware that they’re infected. And, as Ryder says, if you eschew condoms, you may end up risking your life.

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