Female sexual function and dysfunction are perhaps at the core of current sex research. Recent systematic reviews (McCool et al., 2018; West et al., 2004) replicate the high FSD prevalence across different populations, making its accurate assessment still an active research area by either improving the existing alternatives (Grover & Shouan, 2020) and offering new ones (Giraldi et al., 2011). Therefore, the present study evaluated the psychometric properties of the FSFI in a Chilean sample, demonstrating the FSFI possesses good structural validity and reliability while being capable of meaningfully compare individuals across relationship status, age generations, regions of Chile, BSDM practices, and paraphilic interests.
Structural validity
The present study provides support for the six-factor solution in Chilean adult women. This latent structure was first proposed by the scale authors when the FSFI was developed (Rosen et al., 2000)—though primarily by following its theoretical model since the data supported a five-factor solution favoring the conflation of desire and arousal. Other validation studies have also found acceptable solutions involving a two- (Wolpe et al., 2017), three- (Chang et al., 2009), four- (Sun et al., 2011), and five-factor (Forbes et al., 2014) solutions, where the five- and six-factor are the most replicated solutions (Neijenhuijs et al., 2019). Thus, there are, at least, two forefronts to address this controversy of the FSFI structural validity: data/psychometrics and the theory.
From the data, as summarized by Neijenhuijs et al. (2019), the structural validity of the FSFI is inconsistent and of low quality according to the consensus-based standards for the selection of health measurement instruments (COSMIN) methodology (Prinsen et al., 2018). Whereas there is no consistent factorial solution obtained through confirmatory factor analysis (CFA), most studies replicating the five-factor solution do so using principal component analysis (PCA), which is considered only indirect support (Kim, 2008). Both techniques allow capturing the variance in variables in a smaller set through data extraction, interpretation, and rotation, choosing the number of factors or components. PCA creates one or more components from a larger set of measured variables through an inductive approach, whereas CFA does the opposite through a deductive, theory-driven approach, where items work as indicators of a latent factor that would best reproduce the observed correlation; variables create components, factors create variables (Tabachnick, 2001). Thus, CFA is considered direct evidence of structural validity. From the theory, sexual desire and arousal often conflate—in the five-factor solution—so much so that, at least for women, it appears that sexual desire could precede sexual arousal, as well as follow it, or be indistinguishable from one another (Brotto et al., 2009; Graham et al., 2004). Following this line of thought, the DSM-V (APA, 2013) introduced revisions that resulted in the reclassification of hypoactive sexual desire disorder and sexual arousal disorder as sexual interest/arousal disorder. However, much like the several other validation studies using CFA replicating a six-factor solution (e.g., Bartula & Sherman, 2015; Burri et al., 2010; Hevesi et al., 2017), there is also evidence against the conflation of sexual desire and arousal demonstrating it is not always a proper fit to the data (Clayton et al., 2012). Similarly, while the present study showed that the six-factor solution provides a better goodness-of-fit to conceptualize sexual desire and arousal as separate (though related) theoretical and empirical dimensions of the sexual response, it is also fair to say the five-factor solution provides acceptable fit indices, and this study evidence does not necessarily put into question other studies supporting the five-factor solution. Moreover, there are still several different layers to consider when using CFA, such as the sociocultural characteristics of the sample, its size, the researcher's subjectivity when analysing the solution, goodness-of-fit indicators, etc. (Kim, 2008), which also influence the ultimate decision of a factor solution. Therefore, it would be unsurprising that the FSFI may show different factor structures in different contexts or samples of relevant characteristics (e.g., Hevesi et al., 2017). Moving forward, our understanding of why there is variability in the structural validity of the FSFI what seems important to know for whom and why a factorial solutions provides a better fit to the data. There are two main ways to ascertain this: through measurement invariance analyses assessing theoretically relevant variables would allow us to understand 'for whom' a conflation between desire and arousal or lack thereof works best, while cross-cultural validations would allow us to understand the reason/why may be the case.
Measurement invariance
As a multifactorial construct, sexual function is highly modulated by sociocultural contexts, such as people's relationship status For instance, women in relationships have better sexual satisfaction and higher sexual self-esteem than single women (Antičević et al., 2017). Particularly, after establishing measurement invariance across relationship status, Park and MacDonald (2022) demonstrated that sexual desire involving a partner in single women, yet not for solitary sexual desire, was negatively related to sexual satisfaction; whereas for those in a relationship, a lower solitary desire and higher sexual desire involving a partner were associated with greater sexual satisfaction. However, in a five-year longitudinal analysis of women in a relationship or single demonstrated that those in a relationship had worse desire, arousal, lubrication, and satisfaction at year five, whereas this was also true for the satisfaction for single women. Conversely, the orgasm function was the only one improving at year five in women in a relationship, and with a much larger magnitude for single women (Gunst et al., 2017). Certain contextual factors, such as being pregnant or having children, have also shown to modulate women' sexual function (DeJudicibus & McCabe, 2002). Yet, when that occurs in interaction of a romantic relationship, relationship satisfaction and perceptions of partner's desire correlated negatively with solitary sexual desire, whereas relationship satisfaction correlated positively with dyadic sexual desire (Cappell et al., 2016). Meanwhile, in a multi-stage, clustered, and stratified population probability sample study of sexually active British women, no association between relationship status, relationship duration or general happiness with the relationship with sexual pain was found (Mitchell et al., 2017), though women who report higher emotional closeness with their partners have lower odds of experiencing sexual pain (Fergus et al., 2020). Altogether, it is clear the influence that being or not in a relationship has on female sexual function (FSF) is highly dependable on several factors. Thus, this study's findings demonstrate that the FSFI is a reliable capable to meaningfully address relationship status as a (co)variable to explore in future FSF studies.
When it comes to age, it is worth remembering that sexual function problems can be experienced at any point in the individuals lives (APA, 2013). However, studies consistently show that FSF tends to worsen with age (Berman et al., 1999; Clayton & Harsh, 2016; McCool et al., 2018). In a large study conducted in the US with 31,581 women, the prevalence of self-reported sexual problems involving desire, arousal, and orgasm-related increased linearly with age. Yet, the levels of distress due to sexual problems were the lowest in elderly women (12.6%) in comparison to middle-aged and younger women combined (25%; Shifren et al., 2008). Adolescents and younger adults are not except of FSD (O’Sullivan, 2015). Among women between 18–29 years old, with at least one partner in the past year, the rate of FSD ranged between 19 to 32% (Laumann et al., 1999), meanwhile another study reported that FSD rates increased with age starting at 26.2% for 18–19 years old, moving up to 44.3% for 20–29-year-olds, and 41.2% for 30–39-year-olds (Song et al., 2008). Amongst the natural endocrine events that come with time and choice, pregnancy and menopause are two important events that strongly modulate women' sexual function. For instance, pregnancy and postpartum are associated with a drastic reduction in desire, pain on intercourse, impediments, or decreased ability or fear of achieving orgasm (Clayton & Harsh, 2016). The prevalence of sexual problems in women that go through childbirth ranges between 41–83% during the two to three months after delivery (Fehniger et al., 2013; Leeman & Rogers, 2012). Though, key elements influencing the return to enjoyable sexual activity after childbirth involve more than just recovering from perineal trauma, dealing with vaginal dryness due to breastfeeding, or managing the impacts of postpartum depression treatment, as well as sufficient rest, while fostering a suitable environment for intimacy (Leeman & Rogers, 2012). Finally, an study with women ages 57 to 85 showed that the most common sexual problem for elder women are low sexual desire (43%) and reduced vaginal lubrication (Lindau et al., 2007). Clearly, as people age, there is a general decline in health, that in combination with other psychosocial changes and life events associated with adult life, conspire against women' sexual function (Ambler et al., 2012). Therefore, the present study provides the first demonstration that the FSFI is capable to meaningfully compare across different age groups, allowing future studies to explore these intersectionalities in FSF.
When it comes to geographical location, cross-cultural findings on FSF often show variations (McCool et al., 2016). For example, in the context of Latin America, and while using a sample of women between 40 to 59 years old from 11 countries, Blümel et al. (2009) showed that FSFI total scored varied between 20.6 to 29.9, while the percentage of FSD ranged between 21–98.5%. One way to understand these differences is through the erotic equity model which proposes a socio-structural analysis as to how a system enables or fail to promote positive aspects of sexuality and wellbeing (Higgins et al., 2022). Therefore, a greater financial, educational, and job limitations would lead to a poor sexual wellbeing, especially sexual satisfaction and overall functioning. Particularly, Chilean studies on FSF have been conducted almost exclusively with women from our capital city. Moreover, judging by the concentration of votes our last presidential elections, our country's provinces concentrate different political ideologies or views (García, 2021), which have also shown to be indirectly associated with sexual satisfaction (Sánchez-Fuentes et al., 2016), and to modulate sexual behaviors such as people's dating strategies (Tybur et al., 2015). Furthermore, Herrera and Pino (2023) showed that when creating two new provinces there was an increase in mean, median, and mode of individual's income in one of the provinces (i.e., Los Ríos), while not in the other (i.e., Arica y Parinacota), suggesting that other financial and sociocultural factors interact with that process. For instance, for the year 2022, Los Ríos's gross domestic product (GDP) was nearly double than Arica y Parinacota's (4.410M vs 2.610M USD; Banco Central de Chile, 2023). When comparing the FSFI scores between Santiago (2022 GDP = 139.921M USD) and the rest of the country, the financial inequities do not reflect higher FSFI scores in favor of Santiago (Supplemental Tables 3 and 4). In fact, significant difference were found in the 'orgasm' and 'satisfaction' dimensions, where the south scores in the 'orgasm' sub-scale were significantly lower than the rest of Chile, while Santiago scores in the 'satisfaction' subscale were significantly lower than the rest of Chile (ps < 0.05). However, the magnitude of the differences were very small (Cohen's d = .23; d = .42, respectively), thus demonstrating the multifactorial nature of sexual wellbeing and sexual function. Whereas the erotic equity model hypothesis did not explain the FSFI score differences found in the Chilean population, the present study still provides the first demonstration that the FSFI is capable of meaningfully compare amongst regions of Chile. This is of special interest for the CSSS future studies focused on people' sexual function, and its relationship with socio-demographic variables, in a country whose sexual research has been deemed outdated and limited (Quintana, 2023).
When it comes to sexual behaviors, the extensive range of human sexual behaviors can be categorized between those normative or frequent (Herbenick et al., 2010) and non-normative, and while these distinctions aren't always sharply defined, the latter generally encompasses sexual activities, expressions, and behaviors that are less common within the population (Pfaus et al., 2020; Wismeijer & van Assen, 2013), often associated to the BSDM community (Ambler et al., 2017). Given these behaviors and the BSDM community have suffered from a long history of stigma of being deviant, immoral, non-natural, etc. (Bering, 2013), researchers have been interested in exploring differences between BDSM and non-BDSM practitioners. While some studies show no differences (Monteiro Pascoal et al., 2015), more frequently studies report a significant better sexual function and wellbeing of BDSM practitioners and people from the BDSM community than the general population (Botta et al., 2019; Monteiro Pascoal et al., 2015; Strizzi et al., 2022; Wismeijer & van Assen, 2013). This is not to say that BDSM practitioners do not suffer from, at least, some degree of sexual dysfunction (Huang et al., 2023). Interestingly, a comparison between people who perceive themselves as either sexually dominant or submissive demonstrated that dominant men had more biological male children (Jozifkova & Kolackova, 2017). Curiously, this relates to findings in animals where sexual fetishes not only modulate reproductive yield (Cetinkaya & Domjan, 2006), but also sexual arousal, as well as partner preference (Quintana, Desbiens, et al., 2019; Quintana, González, et al., 2019). Finally, across all variables of interest for the measurement invariance analyses, only did BDSM practitioner showed significant differences when comparing across its sublevel, where BDSM practitioners had a significant higher scores in five out of seven FSFI dimensions, and lower risk of scoring below the FSD criterion than non-BDSM practitioners (see Supplementary Tables 2 and 3), corroborating previous findings. Altogether, the FSFI demonstrates to be a valuable tool to meaningfully compare across people who do and do not perform BDSM behavior, which proves of great value for the study of sexual wellbeing of the BDSM community.
Finally, when it comes to paraphilic interests, there is only study on this population' sexual function, and yet paraphilia-associated sexual arousal patterns estimates may go as high as 62.4% in the population (Ahlers et al., 2011). Castellini et al. (2018) assessed the relationship among paraphilic thoughts and behaviors, hypersexuality, and psychopathology in a sample of university students. They showed, amongst other findings, that, aside for sadistic and transvestic behaviors, women with paraphilic behaviors (i.e., voyeurism, exhibitionism, fetishism, masochism, frotteurism, and pedophilia) scored higher than those without them across all domains of the FSFI. However, there are many studies addressing different component of it individually. For instance, Mundy and Cioe (2019) demonstrated that individuals with criminal or combined paraphilic interests experienced lower sexual satisfaction without engaging in paraphilia-related behavior, while those solely interested in legal paraphilias showed unaffected satisfaction. Moreover, disclosure to partners correlated with higher satisfaction, regardless of paraphilic interest or engaging with the partner in these behaviors. Our study found no significant differences in terms of FSF, FSD, nor across the criterion variable scores between people with paraphilic interest. Whereas null results often fall short in demonstrating the relevance in findings, these results demonstrate that are perhaps not only perhaps the first assessment of women with paraphilic interests' sexual functioning, but they also demonstrate that this group does not differ significantly sexual functioning and wellbeing from those who do not manifest the same interests. Similarly, the present study is also the first demonstration the FSFI is able to compare between paraphilic interests and lack thereof, allowing future studies to meaningfully compare these groups along with other FSF-related constructs.
Limitations and future studies
The study caveats need acknowledgment. Firstly, our study did not involve a clinical group diagnosed with sexual dysfunction, a recognized gold standard for ascertaining the presence of Female Sexual Dysfunction (FSD). This omission hindered the assessment of FSFI's sensitivity and specificity in the Chilean population. Secondly, the study was conducted during the SARS-CoV-2 pandemic's second wave, limiting the sample size, and potentially biasing results towards lower sexual function scores (Quintana, 2022). Future research should assess the potential impact of pandemic-related factors on scores. Thirdly, the online nature of the study restricted participation to individuals with internet access, affecting sample diversity and representativeness. Lastly, the sample primarily comprised cisgender and heterosexual individuals despite attempts to include gender-diverse participants (Quintana, 2023), falling short of the intended diversity. Future studies must actively recruit a wider gender and sexual orientation sample and analyze FSFI measurement consistency across these identities.