Can Men Develop Bacterial Vaginosis?
No, men cannot develop bacterial vaginosis (BV) because BV is a condition that specifically affects the vaginal microbiome—an anatomical structure men do not possess. However, men can carry BV-associated bacteria on their penile skin and may play a role in transmitting these organisms back to their female partners, contributing to recurrent infections. 1, 2
Understanding BV-Associated Bacteria in Men
Men can harbor BV-associated bacteria (BVAB) on their penile skin, serving as a potential reservoir for reinfection of female partners, though they remain completely asymptomatic. 3
BV-associated bacteria in the Clostridiales order have been detected in male partners of women with BV, supporting the hypothesis that male genitalia colonization may contribute to persistence of infection in women. 3
The epidemiologic data shows female-to-male transmission of G. vaginalis (a key BV organism) is more common than male-to-female transmission, explaining high concordance rates of bacterial carriage among couples. 4
The Sexual Transmission Debate
Traditional CDC guidance has stated that BV is not a classic sexually transmitted infection and that treating male partners does not prevent recurrence, based on six older randomized trials. 5 However, this recommendation has been challenged by newer evidence. 1
Women who have never been sexually active rarely develop BV, and the condition is strongly associated with multiple sex partners and frequency of intercourse, suggesting sexual activity enhances disease development even if direct transmission is not the primary mechanism. 1, 4
A landmark 2025 randomized controlled trial (the StepUp trial) fundamentally changed this understanding: treating male partners with combined oral metronidazole (400 mg twice daily) and topical 2% clindamycin cream (applied to penile skin twice daily for 7 days) reduced BV recurrence from 63% to 35% within 12 weeks (absolute risk difference of -2.6 recurrences per person-year, P<0.001). 2
Current Treatment Recommendations for Male Partners
ACOG now recommends that male partners of women with recurrent BV receive treatment, including metronidazole 400 mg orally twice daily for 7 days and 2% clindamycin cream applied to penile skin twice daily for 7 days. 1
This represents a significant shift from historical practice, where the six older trials showing no benefit were critically flawed with suboptimal treatment regimens, poor adherence monitoring, and insufficient statistical power. 6
Both partners should avoid all alcohol during metronidazole treatment and for 24 hours after completion to prevent disulfiram-like reactions, and refrain from unprotected intercourse for at least 14 days to allow treatment to take effect. 1
Clinical Pitfalls to Avoid
Do not confuse the inability of men to develop BV (a vaginal condition) with their potential role as asymptomatic carriers of BV-associated bacteria. 3
The older evidence base against treating male partners was methodologically flawed—the 2025 StepUp trial provides the highest quality evidence to date and should guide current practice for recurrent BV cases. 2, 6
No routine follow-up is needed for asymptomatic male partners after treatment, but women should return if symptoms persist or recur. 1