If a young woman has expressed history of sexual activity, it is important to explore the various types of sexual behaviors she engages, as well as, the gender of those partners. Assessment of sexual behavior should be done first by starting with an open-ended question like, “have you ever had sex?” or “what have you done sexually with a partner?” [5]. Once a young woman discloses that she has a female sexual partner, it is important to explore her specific sexual practices with that partner. While research is limited about the prevalence of specific sexual practices that adolescent WSW engage in with their female sexual partners, accurate histories should be sought in each clinical encounter. Qualitative research in adult WSW has shown that these women frequently report oral sex, digital penetration “fingering,” and vaginal grinding or bumping as common sexual practices and less frequently the use of sexual toys [6]. It is important to note that not all WSW engage in oral sexual intercourse with their female partners, and providers should not assume that this is a sexual behavior for their WSW patients. Table 14.1 also includes detailed sexual behavior questions that include the types of sexual intercourse (oral, vaginal, anal, etc.) that young women may engage in. If practicing oral sex, patients should be encouraged to use a barrier such as a dental dam or plastic wrap. When using sex toys , such as dildos and vibrators, patients should be instructed to clean and disinfect them after use and cover them with a condom during sex when possible.

Although WSW may have lower risk of HIV/AIDS than women who have sex with men (WSM), it is important for these women to practice safe sex. There is limited data on the risk for STI transmission between female sexual partners. The risk of STI is thought to vary by the specific STI and sexual practice (e.g., oral-genital sex; vaginal or anal sex using hands, fingers, or penetrative sex items; oral-anal sex) [3]. Practices involving digital-vaginal or digital-anal contact, particularly with shared penetrative sex items, present a possible means for transmission of infected cervicovaginal secretions [7]. This is complicated by the fact that majority of WSW also report sexual history with male partners, therefore, increasing the risks acquiring STIs from their male partners and transmitting them to their female partners [8]. Report of same-sex behavior in women should not deter providers from considering and performing screening for STIs [8].

Several studies have shown that adult populations of WSW have significant rates of STIs such as chlamydia and trichomoniasis . The CDC recommends screening T. vaginalis in women seeking care for vaginal discharge and also recommends screening once for HIV in all persons older than 13 years of age and annually or sooner for those at high risk for infection that includes women who have new or multiple partners, have a history of STDs, exchange sex for payment, or use injection drugs [7]. In large study of over 9000 sexually active women, ages 15–24, presenting for care at a family planning clinic, C. trachomatis positivity among the WSW and WSMW participants was 7.1% compared with 5.3% among the purely WSM [9]. Risks for C. trachomatis positivity were comparable across groups and included younger age (<20 years), nonwhite race/ethnicity, new sex partner, symptomatic sex partner, and current clinical symptoms [9]. The reports of same-sex only behavior in women should not deter providers from screening these women for STIs including chlamydia [7]. The CDC and the USPSTF recommend routine annual screening for C. trachomatis in all sexually active female aged ≤25 years (Grade B recommendation) [7].

Other common causes of vaginal discharge in WSW are bacterial vaginosis (BV) and candidiasis [10, 11]. The etiology of BV remains uncertain, but is characterized by disruption of the normal vaginal microbiome which includes a depletion of lactobacilli and overgrowth of anaerobic and highly fastidious bacteria that include Gardnerella, Prevotella species, Mycoplasma hominis, Bacteroides spp., Peptostreptococcus spp., Fusobacterium spp., Mobiluncus spp., and Atopobium vaginae [12]. A large representative sample of US adolescent and adult women ages 14–49 found that almost one third of women (29%) were positive for BV and that higher prevalence rates were associated with increasing age, Black and Hispanic race, low socioeconomic status, and recent history of douching [12]. A convenience sample of African-American WSW women seeking care at a STD clinic in Mississippi found that of the almost 200 women recruited, almost half (47.4%) were diagnosed with BV [10]. They also found that BV infection was almost twice as likely in women with bisexual identity, douching in the past 30 days, and report of more than one lifetime male partner [10]. There is no routine screening recommended for BV in asymptomatic WSW (see Table 14.2 for summary of diagnostic testing for BV), but we recommend that any WSW who presents with complaints of vaginal discharge should be screened for BV.