Vaginal & Intimate Health

Can you get BV from a man? I explain what actually causes bacterial vaginosis and why it isn't classified as an STI.

Can You Get BV From a Man? An OB/GYN Explains

July 15, 2026

You typed his name into the question without meaning to. Not directly, but it was there. Underneath “can you get bacterial vaginosis from a man” was really “did he do this to me.” Maybe you have a new partner. Maybe you have been with the same one for years and this is the third round of the same infection. Either way, some part of you has already run through what he might be carrying, who he might have been with, whether this is something he is passing to you without either of you knowing. Here is what actually happens in your body, and it is not what you have been picturing. The answer is not mostly about what he is carrying. It is about your own chemistry reacting to his, and once you understand the difference, the blame stops making sense.

Quick answer: Not the way you might think. Bacterial vaginosis is not classified as a sexually transmitted infection. It develops when your own vaginal bacteria overgrow, most often because semen shifts your vaginal pH away from its normal acidic range. A male partner can carry the same bacteria without symptoms, or develop a different condition of his own called urethritis, but he is not giving you an infection the way an STI works.

I'm a board-certified OB/GYN, and in this video I break down what actually happens between partners when bacterial vaginosis is in the picture.

What Bacterial Vaginosis Actually Is

Bacterial vaginosis, or BV, is an infection of the vagina caused by bacteria that already live there in small amounts. In a healthy vagina, this bacteria is part of your normal flora, the microbiome that keeps your environment stable, not an outside invader. Problems start when it overgrows.

The Bacteria Behind It

Gardnerella vaginalis is the bacteria most commonly linked to BV, though the medical community is still working out the full picture. Several other organisms are frequently involved too, including Leptotrichia, Sneathia, Megasphaera, and Clostridiales. Testing can sometimes identify which bacteria is driving your particular case, but the treatment does not usually change based on the result.

Why a Man Cannot Get BV Himself

A man cannot develop bacterial vaginosis. He does not have a vagina, so the infection as it is defined in you simply does not apply to him. He can carry the same bacteria on his skin, his penis, and his scrotum without it causing him any problem at all. Carrying the bacteria and having an infection are two different things, for him and for you.

What Symptoms Actually Look Like

BV can show up as a change in discharge or a new fishy odor, especially noticeable after sex. Plenty of women have no symptoms at all and only find out during a routine exam. Do not assume nothing is wrong just because you feel the same as always, and do not panic if your doctor finds it without you ever noticing a change.

Semen, Not Transmission, Is the Bigger Driver

This is the part that changes how you think about the question. Bacterial vaginosis is not usually something a man gives you the way a classic infection works. Most often, it develops because semen changes the chemistry inside your vagina.

Your Vagina Is Built to Stay Acidic

A healthy vagina holds a pH between 3.8 and 4.5. That acidity keeps the bacteria already living there in balance. Semen sits closer to neutral or slightly basic. When semen enters your vagina, it temporarily pushes your pH up and out of that protective range.

Why That Shift Matters More Than Carriage

Once your pH rises, the bacteria already inside your vagina have more room to overgrow. This is the mechanism behind most cases connected to a partner, not bacteria being passed from his body into yours. A man can carry Gardnerella on his skin and never transmit anything harmful to you. It is his semen’s chemistry, not his bacteria, that usually tips the balance. I want you to hold onto that distinction, because it changes what you should actually be worried about.

For the fuller mechanism behind this pH shift, including everything else besides semen that can raise it, see my guide on whether a man can throw off your pH balance.

What Urethritis Means for Him

Men are not left out of this picture entirely. They can develop urethritis, a related but distinct condition.

Shared Symptoms, Different Anatomy

Urethritis is inflammation of the urethra, the tube a man urinates through. It can cause unusual discharge, odor, and pain with urination, symptoms that closely mirror what you might notice with BV. Many women with BV have no symptoms at all, so the overlap does not always show up the way you would expect.

Because a UTI, urethritis, and BV can all cause similar discomfort, self-diagnosis at home is genuinely difficult. If anything feels different, new, or unusual, seeing your doctor is the fastest way to know what is happening rather than guessing between three conditions that look alike. This applies to him too. A man noticing new discharge or discomfort should see his own doctor rather than assume it is connected to your diagnosis.

Is the Connection Actually Settled?

Male urethritis is common. One peer-reviewed cohort study found an incidence of roughly 56 cases per 100 person-years among men with female partners. Researchers have found Gardnerella and other BV-associated bacteria in male urethral samples, but a 2022 study looking specifically for a causal link found these bacteria were actually more common in men without urethritis symptoms than in men with it. A direct cause and effect relationship remains unproven.

That finding matters more than it might seem. It suggests that finding these bacteria in a man’s urethra is more likely a sign of recent exposure than proof he is causing anyone’s infection, his own or yours. Testing which bacteria he might be carrying will not change what either of you needs to do about it.

	Bacterial Vaginosis (Her)	Urethritis (Him)
Where it happens	Vagina	Urethra
Common bacteria	Gardnerella vaginalis, others	Often the same organisms, causal role unproven
Discharge	Common, sometimes unnoticed	Common, often noticeable
Pain with urination	Possible	Possible
Main driver	Vaginal pH shift from semen	Not fully understood

Can BV Pass Between Female Partners?

Yes. Bacteria can move between any two partners regardless of gender, and female partners are not an exception.

What the Research Shows

Bacterial vaginosis is also common between female partners. Studies estimate BV prevalence somewhere between 22% and 52% among women who have sex with women, and shared use of sexual accessories is an independent risk factor. That pattern points to a distinct mechanism, direct transmission of vaginal fluid through skin-to-skin contact or shared accessories, not the semen-driven chemistry described above.

If you have sex with women and notice a recurring pattern, this transmission route is worth mentioning to your OB/GYN directly. The usual “did he give this to me” framing simply does not apply here.

Does Your Partner Need Treatment?

Not for a single episode. Having BV does not mean your partner has an infection, and it does not mean you caught it from him.

The Standard Recommendation

Current guidance does not call for treating a male partner every time you have BV once. The bacteria driving your infection was very likely already living in your vagina, simply overgrowing under the right conditions. Treating him does not address what actually happened in your body, and it can leave you assuming a problem is solved when the real driver was never his to fix.

If BV keeps returning with the same partner, that is a different and more specific conversation. I cover what changes when BV keeps recurring with the same partner, including when partner treatment becomes worth discussing in a separate guide. This article is about a single episode and what caused it, not a repeating pattern.

Lowering Your Risk Without Overselling Condoms

Prevention here is honest, not oversold.

Condoms Help, With a Caveat

Condom use is linked to a modest reduction in BV risk, but the research is more mixed here than it is for classic STIs. At least one study found that direct semen exposure, not condom use itself, was the stronger predictor of a new BV episode, meaning the barrier matters mainly because it blocks semen contact rather than acting as a general BV shield. Use condoms consistently, especially with a new partner whose infection or STI status you do not know, for your protection and his. This matters in both directions. A female or male partner can also be carrying something you have not been told about.

If BV Is Already Present

Semen is only one of several things that can shift your vaginal pH, and prevention only matters going forward, not for an infection you already have. For treatment options once BV is already present, see how to get rid of BV without antibiotics and how boric acid works for BV.

When This Is Bigger Than One Infection

One episode of BV traced to semen chemistry is common and usually not a sign anything deeper is wrong. A vaginal environment that struggles to hold its acidic balance again and again is a different story.

Estrogen supports the healthy bacteria that keep your vagina acidic. When estrogen is low or your cycle is irregular, that balance is harder to maintain even without a partner involved at all. Insulin resistance, thyroid shifts, and cortisol patterns can all make a vaginal environment more fragile than any single lifestyle fix can address.

This is where I tell my patients to look beyond the immediate infection. If BV or similar symptoms keep resurfacing no matter what you change, I created the Ultimate Hormone Assessment to map the hormonal patterns behind exactly this kind of recurring pattern, not just hand you another round of treatment.

Frequently Asked Questions

Can a man give you bacterial vaginosis?

Not in the way a classic infection works. BV develops when bacteria already living in your vagina overgrow, most often because semen temporarily raises your vaginal pH out of its protective range. A man can carry the same bacteria without symptoms, but he is not infecting you the way an STI would. This is why BV is not classified as a sexually transmitted infection.

Can BV be passed between female partners?

Yes. Bacterial vaginosis prevalence among women who have sex with women is estimated between 22 and 52 percent, and shared sexual accessories are an independent risk factor. This supports direct transmission of vaginal bacteria between female partners, a distinct mechanism from the semen-driven pattern common in opposite-sex encounters. If this applies to you, mention it directly to your OB/GYN.

Does my partner need treatment if I have BV?

Not for a single episode. Having BV does not mean he has an infection, and it does not mean you caught it from him. The bacteria was very likely already living in your vagina before it overgrew. Partner treatment becomes a more relevant conversation only when BV keeps recurring with the same partner.

What is urethritis, and can I give it to my male partner?

Urethritis is inflammation of the urethra in men, causing symptoms similar to BV like discharge and pain with urination. Male urethritis is common on its own. Researchers have found BV-associated bacteria in male urethral samples, but a 2022 study found these bacteria were actually more common in men without symptoms, so a direct causal link between your BV and his urethritis remains unproven either way.

Is bacterial vaginosis considered an STI?

No. BV is not classified as a sexually transmitted infection. It results from an imbalance of bacteria that already lives in your vagina, not from acquiring a new pathogen from a partner, even though sexual activity and semen exposure can influence when it develops. That distinction is exactly why the standard advice does not include treating a partner for a single episode.

This content is for educational purposes only. It is not diagnostic and is not a substitute for personalized medical advice from your provider.