Sexual health

STIs Between Women: Real Risks, Right Tests

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Sex between women is not risk-free. HPV, herpes, trichomoniasis, and bacterial vaginosis can pass through skin contact, shared fluids, or shared toys, and HIV risk is lower but not zero. Cervical screening still applies to anyone with a cervix. Barriers and testing with new partners reduce the risk.

Last updated: July 2026

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Can two women pass STIs to each other?

Two women can pass sexually transmitted infections to each other, and the idea that this kind of sex carries no risk is a widespread misconception. Skin-to-skin contact, shared vaginal fluids, menstrual blood, and shared sex toys can all move an infection from one partner to another. According to the World Health Organization, STI screening is relevant to women regardless of the gender of their partners 1. Fewer women who have sex only with women are offered testing, which means infections can go unrecognized rather than being genuinely absent. Learning how to tell if you have an STI is a useful starting point.

Which infections transmit between female partners?

Several common infections move readily between female partners. HPV spreads through genital skin-to-skin contact and is so common that it causes more than 95% of cervical cancers, so two women can share it easily 2. Trichomoniasis, a curable parasite, and bacterial vaginosis, an imbalance of vaginal bacteria, can both transfer through shared fluids or toys, and bacterial vaginosis is often found in both partners at once 3. Herpes and syphilis can also pass through skin and mucous-membrane contact, which is why testing is offered regardless of partner gender 1. You can read more about bacterial vaginosis and about how HPV behaves.

Do you still need Pap and HPV screening?

Pap and HPV screening still applies to anyone with a cervix, whatever the gender of their partners. HPV does not require penetration or a male partner to spread, so women who have sex only with women can still carry high-risk types and develop cervical changes 2. Professional guidelines recommend a Pap every 3 years from age 21, with a Pap plus HPV test every 5 years offered for ages 30 to 65 4. The HPV vaccine is highly protective, and one landmark trial found it close to 98% effective against high-grade cervical lesions caused by its target types 5. Skipping screening because a partnership feels low-risk is one way these changes are missed, so see how often to get a Pap smear.

What lowers the risk between partners?

A few practical habits meaningfully reduce transmission. Covering or washing shared sex toys between uses and between partners, using barriers such as dental dams or gloves, and avoiding shared toys during an active infection all cut down on exposure 1. Getting tested with a new partner, and treating both partners when trichomoniasis or another curable infection is found, prevents the back-and-forth reinfection that testing one person alone misses 3. The HPV vaccine adds durable protection against the types that cause most cervical disease 5. Screening needs also shift across life, from adolescents beginning first relationships to women in perimenopause, so age alone does not remove the value of a check 1. A brief check-in with each new partner keeps small risks from turning into repeated reinfection.

When STI screening deserves a clinician's input

A clinician is the right person to sort out which tests fit your history. New symptoms, a partner's diagnosis, an abnormal Pap, or simply never having discussed testing as a same-sex couple are all reasons to raise it with a primary care clinician 1. Care that assumes every patient has male partners can leave gaps, so being direct about your relationships helps a clinician order the right screening 1. There is no judgment in asking, and you can plan ahead by reading how to bring up sexual health at a visit. Gale can help you prepare for that conversation.

Common questions

Some infections are transmitted less efficiently, but lower is not none. HPV, herpes, trichomoniasis, and bacterial vaginosis can all pass between female partners, so screening still matters.

Yes. HPV spreads through genital skin contact and does not require a male partner, so anyone with a cervix should follow standard Pap and HPV screening regardless of partner gender.

It appears so. Bacterial vaginosis is more common when both partners have it, which suggests the balance of vaginal bacteria can be shared, though it is not a classic sexually transmitted infection.

Covering or washing shared toys, using barriers such as dental dams or gloves, getting tested with new partners, and considering HPV vaccination all help reduce transmission.

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When to check in about STI risk

  • —New genital sores, unusual discharge, or pelvic pain is a reason to seek clinician review.
  • —An abnormal Pap result or a partner's STI diagnosis is a reason to arrange testing with a clinician.
  • —Fever with pelvic pain can signal a spreading infection and is a reason to seek prompt medical care.
  • —Symptoms that keep returning after treatment, in you or a partner, is a reason to seek clinician review.

This article is general health education, not medical advice. Which STI tests and screenings you need should be decided with a primary care clinician or gynecologist who knows your history.

References

  1. 1.World Health Organization (2022). WHO guideline on self-care interventions for health and well-being, 2022 revision. World Health Organization (WHO). link ✓WHO's self-care interventions guideline supports STI screening as part of women's health across the whole life course and endorses self-collected samples as a reliable, accepted testing option.
  2. 2.World Health Organization (2026). Cervical cancer (fact sheet). World Health Organization (WHO). link ✓WHO states that HPV is very common, causes more than 95% of cervical cancers, and can persist without symptoms for years before it is detected.
  3. 3.MedlinePlus (National Library of Medicine) (2024). Vaginitis. MedlinePlus, U.S. National Library of Medicine (NIH). link ✓MedlinePlus describes trichomoniasis and bacterial vaginosis as causes of vaginitis, notes trichomoniasis is a common curable sexually transmitted infection, and that such infections may cause few or no symptoms.
  4. 4.American College of Obstetricians and Gynecologists (2016). Practice Bulletin No. 168: Cervical Cancer Screening and Prevention. Obstetrics & Gynecology. doi:10.1097/AOG.0000000000001708 ✓ACOG cervical screening guidance provides the recommended Pap interval of every 3 years from age 21 and Pap-plus-HPV co-testing every 5 years for ages 30 to 65, and clarifies that a Pap is distinct from an STI panel.
  5. 5.FUTURE II Study Group (2007). Quadrivalent vaccine against human papillomavirus to prevent high-grade cervical lesions. New England Journal of Medicine. doi:10.1056/NEJMoa061741 ✓The FUTURE II trial reported the quadrivalent HPV vaccine was close to 98% effective against high-grade cervical lesions caused by the vaccine's target HPV types in the per-protocol population.

5 sources, numbered by first appearance. General health information, not medical advice. AI-assisted editorial content — every citation independently verified. Editorial policy

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