Women’s Sexuality, Well-Being, and the Menstrual Cycle: Methodological Issues and Their Interrelationships
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- Brown, S.G., Calibuso, M.J. & Roedl, A.L. Arch Sex Behav (2011) 40: 755. doi:10.1007/s10508-010-9630-3
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Although many studies report that women’s sexual behavior varies across their menstrual cycles, the research findings remain inconsistent. In this study, we addressed two methodological issues in research on the menstrual cycle: how ovulation is measured/inferred and whether data using menstrual cycles or participants’ scores averaged across cycles as units of analysis yield similar results. We also employed an abstinent comparison group in addition to examining how emotional well-being was related to libido and sexual behavior through factor and regression analysis. Data were obtained from 97 participants. There were no significant differences in the results of analyses performed using cycles with known LH surges to determine ovulation versus cycles based on backward counts. However, we concluded that statistical power might be compromised when the known timing of ovulation was less accurate. Likewise, we found few overall differences in the results when we analyzed data using cycles with known LH surges compared to participants’ averaged data across cycles. Women, including those in the abstinent group, reported increased sexual behavior prior to ovulation. Allosexual behavior was positively related to libido, and negatively related to positive and “premenstrual” emotional factors. Autosexual behavior was predicted by libido and an energetic/creative emotional factor. Our findings support hypotheses that women’s sexual behavior is related to both mating and pair-bond formation.
KeywordsEmotional well-beingSexual orientationLH surgeLesbiansMenstrual cycleOvulation
Much of the evidence to date supports the idea that women are continuously sexually receptive throughout a menstrual cycle but experience changes in their sexuality just prior to and at the time of ovulation (Gangestad & Thornhill, 2008) and, perhaps, premenstrually (Englander-Golden, Chang, Whitmore, & Dienstbier, 1980). Wilcox, Weinberg, and Baird (1995) found that women were fertile several days prior to and on the day of ovulation and later reported that intercourse frequency peaked on the day preceding and on the day of ovulation (Wilcox et al., 2004). Likewise, Bullivant et al. (2004) found that sexual activity was elevated for the 3 days prior to and 2 days after the luteinizing hormone (LH) surge. Women ovulate 24–36 h after the LH surge. However, other research has reported no significant differences in sexual activity across the menstrual cycle (Brewis & Meyer, 2005), differences in female-initiated but not male-initiated sexual activity at mid-cycle (Adams, Gold, & Burt, 1978), differences in the timing of inter-pair versus extra-pair copulations across the cycle (Bellis & Baker, 1990), and differential sexual attraction to men other than their partners at mid-cycle (Haselton & Gangestad, 2006).
Summary of selected articles examining sexual differences across the menstrual cycle
Definitions of phases or ovulation
Number of phases/days
Adams et al. (1978)
Backward count; Days on standardized 28 day cycle
Female-initiated but not male-initiated sexual activity increased mid-cycle
Bellis and Baker (1990)
No age data
Forward count on retrospective data; Days on standardized 28 day cycle
Intrapair copulations peaked in luteal phase; extrapair copulations peaked pre-ovulatory and were positively correlated with probability of conception
Brewis and Meyer (2005)
Forward count on retrospective Day 1 of menstruation
No evidence that sexual behavior is related to menstrual cycle phase
Bullivant et al. (2004) (2 studies)
19 = 5 cycle
46 ≥ 1 cycle
Ovukit (LH surge); cervical mucus; BBT and pregnanediol-3-glucuonide
Sexual activity, libido and fantasies peaked around ovulation
Burleson et al. (2002) (lesbians, L & heterosexuals, H)
L = 89
H = 139
BBT; cervical mucus
Allosexual behavior peaked in the follicular phase; autosexual behavior in the follicular and ovulatory phases
Englander-Golden et al. (1980)
Backward count to day 13
Peaks in sexual arousal at ovulation (day-13) and pre-menstrually
Gangestad et al. (2002)
Ovusign to detect LH surge
Women initiated and engaged in sex near ovulation; women reported increased attraction and fantasies about men other than their partners and more partner vigilance near ovulation
Garver-Apgar, Gangestad, and Thornhill (2008)
M = 21.9
Backward count to day 15 (estimated day of LH surge)
Estimated reproductive hormone levels
Estimated estrogen and progesterone levels correlated with symmetry preference
Graham et al. (2000)
Clearplan easy for LH surges
Women reported higher levels of sexual arousal during the periovulatory rather than follicular phase
BBT or backward count to day 14
Female-initiated (autosexual and with partner) and male-initiated sexual activity peaked at mid-cycle
Haselton and Gangestad (2006)
Backward count to day 15
Women mated to men with low sexual versus investment attractiveness were more attracted to men other than their husbands when fertile
Haselton et al. (2007)
Clearblue to detect LH surge
Women judged to dress better when more fertile
Krug, Plihal, Fehm, and Born (2000)
Q-test for LH surge
Women reacted maximally to sexual stimuli, judged the stimuli as less offensive and were more high spirited during ovulation
Laeng and Falkenberg (2007)
Backward count to day 15
Pupil size change was largest to boyfriend during ovulation
Matteo and Rissman (1984)
7 lesbian couples
Backward and forward count standardized like Adams et al. (1978)
Peaks in orgasm, total encounters, self-initiated encounters at mid-cycle; peaks in sexual fantasies during follicular phase
Miller, Tybur, and Jordan (2007)
26.9 ± 5
Forward to days 9–15
Women lap dancers earned more tips in their fertile phase
Pillsworth et al. (2004)
Backward count 15 days based on expected day of next menstruation
Regression on probability of conception
Partnered, but not unpartnered, women reported increasing sexual desire as probability of conception increased
Pipitone and Gallup (2007)
51 (both contraception and normal)
4 equally spaced samples across cycle
In naturally cycling women increased conception risk associated with greater voice attractiveness
Roberts et al. (2004)
Women were rated as more attractive when they were in the follicular phase
Roney and Simmons (2008)
M = 18 (.1 year)
Reported first day of last menses and forward count
Correlation between estimated estrogen level in women and testosterone level in preferred male
Rosen and Lopez (2009)
Forward and backward counts
Women in the fertile phase made more shadowing errors in the presence of a courtship distracter
19 (from PMS clinic) 36 (not from clinic)
M = 34.3 (5.3)
M = 31.2 (5.8)
Estradiol, LH and progesterone levels
Frequency of sexual behavior, female initiated sexual activity, sexual feelings and pleasant thoughts peaked in the mid-follicular phase
Schreiner-Engel, Schaivi, Smith, and White (1981)
Sexual arousal is greater during the follicular and luteal phases
Schwarz and Hassebrauck (2008)
Backward count 15 days
Women were perceived as dressing more provocatively on high fertility days
Sheldon, Cooper, Geary, Hoard, and DeSoto (2006)
56 (30 taking OCs)
M = 21.6 (.9)
Forward count 15 from retrospective 1st day of menstruation
Day of cycle negatively correlated with sex for intimacy
Singh and Bronstad (2001)
M = 22.4 (4.5)
Forward count from retrospective 1st day of menstruation
Women’s scent is more attractive during follicular phase
Slob et al. (1996)
Differences in sexual arousal dependent of time of test not phase of cycle
Stanislaw and Rice (1988)
Day of BBT shift is positively correlated with the day of sexual desire onset
van Goozen, Wiegant, Endert, and Helmond (1997)
Measured estradiol and progesterone in blood via radioimmunoassay
Sexual activity (both masturbation and intercourse) increased around ovulatory phase; and remained high; reported self-initiated sexual activity peaks in the ovulatory phase
Wilcox et al. (2004)
38 (IUD) 30 tubal ligation
Measured estrogen and progesterone metabolites in urine
Intercourse frequency peaks on the day prior to and day of ovulation
The most glaring methodological issue in research on sexuality and the menstrual cycle is how the researchers determined or decided the time of ovulation (Table 1). Some researchers employed physiological measurements to determine the LH surge (e.g., Ovukit: Bullivant et al., 2004; Ovusign: Gangestad et al., 2002; Clearplan: Graham, Janssen, & Sanders, 2000), measured cervical mucus (Burleson et al., 2002), or estrogen and progesterone levels (Sanders, Warner, Backstrom, & Bancroft, 1983) or their metabolites (Wilcox et al., 2004), but most studies employed backward or forward counts from Day 1 of menstruation (Table 1). Similar issues surround differences in the number of menstrual phases defined across a cycle (10 phases, Matteo & Rissman, 1984; 6 phases, Bullivant et al., 2004; 2 phases, Rosen & Lopez, 2009; Singh & Bronstad, 2001), the length of each phase (same length, Singh & Bronstad, 2001 or different lengths, Bullivant et al., 2004; Burleson et al., 2002), if data were broken down by cycle (Brown, Morrison, Calibuso, & Christiansen, 2008a) or averaged across women who contributed different numbers of cycles (Bullivant et al., 2004), and the number of cycles women were followed (usually only one but sometimes up to five cycles). Most researchers defined phases based on women’s hormone profiles (broadly proliferative/follicular with high estrogen levels versus secretory/luteal with high estrogen and higher progesterone levels).
Additionally, when examining the research on the relationship between sexual behavior and women’s menstrual cycles, we failed to find a study that incorporated an abstinent comparison group. Some studies indicated that some of their participants were not engaging in intercourse (Pillsworth et al., 2004) but they did not statistically compare the occurrence of libido and autosexual behavior in the abstinent women with sexually active women.
Another issue in women’s sexuality reflects differences in sexual desire or proceptivity (Hill, 1988) versus pair-bond formation (Diamond, 2003; Gonzaga, Turner, Keltner, Campos, & Altemus, 2006). Women experience both sexual desire/libido and feelings of affection toward others (Diamond, 2003). Libido is probably related to sexual mating while affection is related to pair-bond formation (Gonzaga et al., 2006). Diamond (2003) hypothesized that libido and affection are independent emotional/motivational states that can interact with one another but do not necessarily do so.
If libido and affection are independent, then one should be able to separate their effects. Unfortunately, most research into women’s emotional well-being has concentrated on negative (Hourani, Yuan, & Bray, 2004; Walker, 1997) rather than positive emotional states. However, Brown, Morrison, Larkspur, Marsh, and Nicolaisen (2008b) reported that naturally cycling women experienced fewer negative emotions and more energy at mid-cycle than women using hormonal forms of contraception. In fact, they found that the overall emotional well-being of women using hormonal contraception was more negative than the emotional well-being of naturally cycling women.
In this article, we report on data collected on the menstrual cycles and the sexual desires and behavior of naturally cycling women. In our study, we collected data on cycles with confirmed LH surges but also on cycles without confirmed surges. For the latter cycles, we used a backward count method similar to the ones displayed in Table 1. Therefore, we compared data from cycles with known LH surges with those in which ovulation was estimated using a backward count. We defined five menstrual cycle phases with each phase’s length being 3 days to control for phase length and only examined women between 18 and 40 years of age. Most of our participants were followed for three cycles but many were unable to detect LH surges for each cycle. We, therefore, analyzed data on all cycles with LH surges co-varying out the number of cycles a participant contributed and compared those results with analyses that examined averaged scores across participants who reported one or more LH surges.
Rather than concentrating on sexually active women, we included an abstinent comparison group to compare with our allosexually active heterosexual and lesbian/bisexual women. If sexual behavior does peak during ovulation, we should be able to detect peaks in libido and autosexual behavior in the abstinent women that might be obscured in allosexually active women because of their partner’s desires. Additionally, the relationship between emotional well-being and type of sexual activity was examined.
In summary, we examined two methodological issues concerning research on the menstrual cycle: (1) Do results differ when ovulation and menstrual phase are determined using LH surge and first day of menstruation data versus first day of menstruation and a backward count method? and (2) Do results differ when cycles were used as units of data analysis versus when participants’ averaged scores across cycles were used in the analyses? We also examined specific hypotheses about sexual behavior and the menstrual cycle. First, we tested whether abstinent women exhibited the same patterns of sexuality in terms of libido and autosexual behavior as sexually active heterosexuals and lesbians. Second, we examined how sexual behavior was related to emotional behavior through factor analysis and multiple regression.
The protocols for this study and the consent forms were approved by the institutional review board at the University of Hawaii. The data were collected from January 2005 to December 2007. Participant recruitment occurred at the University of Hawaii at Hilo through classroom visits and campus fliers. Potential participants attended an information session about eligibility. Between 70 and 80% of the participants met the eligibility criteria (see below) and participation rate was 95% of those who met the eligibility criteria. Eighty-nine percent of the participants (N = 136) completed at least one menstrual cycle. At enrollment, participants were told that they would be asked to contribute data (see below) for three menstrual cycles and would be paid $150 for each completed cycle. For this article, we present data on 97 participants who did not use hormonal forms of contraception.
Participants met the following eligibility criteria: (1) aged 18-40 (M = 25.7 years; SD = 5.6); there were no significant group differences in age; (2) reported regular 25–35 day menstrual cycles; (3) not using an intrauterine device; (4) no hysterectomies; and (5) no autoimmune disease or use of medication affecting menstrual cycles, immune system function or reproductive hormones.
Upon enrollment, participants met with a research associate to review study protocols and provide informed consent. Height and weight measurements were taken to determine body mass index (BMI = wt in kg/ht in m2; range, 17.9–44.5; group means were not significantly different). Bioelectrical impedance analysis (RLJ Systems BIA-101A) was used to determine percent body fat (range, 14–45; group means were not significantly different). We measured body mass and percent body fat as potential control variables because too little or too much body mass or fat can influence reproductive hormones (Ferin, Jewelewicz, & Warren, 1993; Siiteri, 1987). Participants received training on how to collect data on their LH surges. The LH surge was determined using Assure Ovulation Predictor kits (the 9-day version, Contraception Technology, San Diego, CA). The length of a participant’s reported cycle determined when she began using the Ovulation Predictor Kit (e.g., if her cycle was 24 days, she began using the kit on Day 4 after menstruation while if her cycle was 30 days, she began using the kit on Day 10 after menstruation). Participants were instructed to test their urine for LH at the same time each day and to read the results within 3–5 min of the test. Participants continued testing their urine until they obtained a positive result or they menstruated. Ovulation occurs between 24 and 36 h after the LH surge. Participants began collecting data on the first day of the next menstrual bleed following the meeting.
Factor analysis on 24 emotions
Burst of energy
Out of control
Number of participants (N), number of cycles with documented LH surges (cycles), and the number of cycles each participant contributed with an LH surge for the analyses
Methods used to determine cycle phase based on whether the LH surge was detected or not (backward count)
Phase of menstrual cycle
LH surge detected
Days 1, 2, 3 after day 1 of menstruation
Days 5, 6, 7 after day 1 of menstruation
Day of LH surge and next 2 days
Days 7,8,9 after LH surge
3 days prior to next menstrual bleed
Days 1, 2, 3 after day 1 of menstruation
Days 5, 6, 7 after day 1 of menstruation
−16, −15, −14 days prior to menstrual bleed
−9, −8, −7 days prior to menstrual bleed
3 days prior to next menstrual bleed
Participants who detected at least one LH surge during the study were divided into three groups: women abstaining from sex for a particular cycle (n = 33); women engaging in sex with only male partner(s) for a particular cycle (n = 45); and women engaging in sex with only female partner(s) (n = 17) or both male and female partners (n = 5). Because all of the latter participants identified themselves as lesbians, we placed them in the lesbian group (n = 22). We analyzed data for these groups in two ways: (1) we used data from all cycles that had an LH surge and (2) we averaged a participant’s data across the cycles she contributed. Therefore, in the first analysis N was based on number of cycles with LH surges and in the second analysis N was based on number of participants contributing at least one cycle with an LH surge (Table 3).
We subsequently examined the data across three independent variables: detectible LH surge or not (2 levels); participants’ sexual behavior (abstinent, heterosexual, lesbian) and menstrual cycle phase (5 levels). Additionally, we tested whether results differed if we examined data from all cycles with LH surges or whether we averaged data across the participants’ cycles.
Experimental Design and Statistical Analyses
Our first analyses examined two methodological issues: (1) Did results differ if ovulation and menstrual cycle phases were constructed using the first day of menstruation and a known LH surge (LH surge) versus using the first day of menstruation and a backward count method (backward count)? (2) Did results differ if cycles with LH surges were used as units of analysis versus using participants’ averaged data across phases for cycles with LH surges? All analyses were conducted using SPSS 15.
We did not examine an effect using a mixed univariate analysis of variance (ANOVA) unless the multivariate effect was significant. To examine whether analyses using LH surge versus backward count methods (Table 4) differed, we used repeated measures ANOVAs. We examined LH surge versus backward count (Method) and the participants’ groups (abstinent, heterosexual or lesbian) across the dependent variables of libido, autosex, and allosex in 2 (Method) × 3 (Group) × 5 (Phases) ANOVAs. These analyses were based on a total of 185 cycles with an LH surge and 71 cycles using a backward count method. We followed up the ANOVAs with pair-wise comparisons and trend analyses.
To examine how sexual behavior and emotions varied across the menstrual cycle, we analyzed data from cycles with LH surges of participants in the abstinent, heterosexual, and lesbian groups and across averaged data per participant (second methodological question). In analyses using LH surges, we covaried out the number of cycles a participant contributed.
We also conducted a factor analysis using a principal components analysis with a varimax rotation across the 24 emotional variables (Table 2). We used participants’ averaged scores for each variable from cycles with LH surges. Using the three factors from the factor analysis, we computed a factor score for each menstrual cycle phase and used multiple regression analysis to examine whether the participants’ three emotional factor scores were related to their libido (using the abstinent, heterosexual, and lesbian groups) and whether libido and the emotional factor scores were related to allosexual (using the heterosexual and lesbian groups) and autosexual behavior scores. We conducted the multiple regression in two ways, using all cycles with an LH surge and cycles averaged across participants. For the multiple regressions, we collapsed the data across the cycle phases by averaging across the phases so that the relationship would be linear rather than curvilinear.
Methodological Issue I: Did Results Differ When the LH Surge Was Used to Determine Menstrual Phase Versus a Backward Count Method?
To test the above research question, we conducted multivariate and univariate 2 (Method) × 3 (Group) × 5 (Phases) ANOVAs across the libido, autosex, and allosex dependent variables. There were no significant main effects for Method (LH surge vs. a backward count method for determining the menstrual cycle phase) whether we used a multivariate analysis F(3, 252) < 1 or the univariate analyses of the sexual dependent variables: libido F(1, 250) < 1, autosex F(1, 250) = 1.4, and allosex F(1, 172) < 1. Additionally, none of the two-way (Method × Groups; Method × Phases) or three-way (Method × Groups × Phases) interactions were significant.
The phase effect was significant across all three dependent variables: libido F(4, 1000) = 16.67, p < .0001; autosex F(4, 1000) = 5.05, p = .001; allosex F(4, 688) = 5.68, p < .0001. We discuss the phase effects in more detail below using data with phases based on the LH surge and cycles as the unit of analysis.
Methodological Issue II: When Multiple Menstrual Cycles Were Examined Across Participants, Did Results Differ When the Data Were Organized by Participants and Averaged Across Cycles Versus When Data Were Organized and Analyzed by Cycles?
Methodological issue II, sexual behavior and cycle phases
Did abstinent women exhibit the same patterns of sexuality in terms of libido and autosexual behavior as sexually active heterosexuals and lesbians?
Using menstrual cycle phase data based on a detected LH surge and cycles as the unit of analysis, we examined whether the groups differed in their sexual behavior across phases. First, the MANOVA across the three dependent variables was significant, F(6, 362) = 18.68, p < .0001. The above significance was predictable given the fact that the abstinent group by definition differed from the heterosexual and lesbian groups in their allosexual behavior. Therefore, we conducted another MANOVA analyzing data for libido and autosexual behavior, which also reached statistical significance, F(4, 362) = 2.84, p = .02. Using univariate analyses and all three groups, the phase effects for libido, F(4, 728) = 22.88, p < .001, and autosexual behavior, F(4, 728) = 5.43, p < .001, were significant. Women’s libido peaked during the ovulatory phase. There was a significant increase in libido from the menstrual to the follicular phase and, again, from the follicular to the ovulatory phase (Table 5). Libido significantly decreased from the ovulatory to the luteal phase, but the luteal and premenstrual phases did not differ from each other (Table 5); this was a significant cubic trend, F(1, 182) = 31.46; p < .001. Women’s autosexual behavior also peaked in the ovulatory phase. There was a significant increase in autosexual behavior from the menstrual to the follicular and ovulatory phases (Table 5). There was a significant decrease in autosexual behavior from the ovulatory phase to the luteal and premenstrual phases; this quadratic relationship was significant, F(1, 182) = 18.84; p < .001. The overall phase effect for allosexual behavior was significant, F(4, 500) = 5.5; p < .001. Sexually active heterosexuals and lesbians engaged in significantly more allosex during their follicular, ovulatory, luteal, and premenstrual phases than in their menstrual phase. Although the pair-wise comparisons did not reflect the subsequent decrease and increase in allosexual behavior, there was a significant cubic trend, F(1, 125) = 11.85; p < .001.
How were the emotional factors related to sexual behavior and libido?
The factor analysis resulted in three factors with eigenvalues >1 and which accounted for 67% of the total variance in emotions. We used variables with loadings greater than .5 in our interpretations of the factors. Factor 1 loaded heavily on emotions involved in premenstrual syndrome, Factor 2 on positive affect, and Factor 3 on energetic/creative (Table 2).
Multiple correlations between emotional factors and sexuality
Positive affect factor
Positive affect factor
Positive affect factor
Although much research has been conducted on how women’s sexual behavior varies across the menstrual cycle, the research findings are not always consistent (Table 1). Part of the reason for the inconsistency is that researchers employ different methods in their work. Our research examined two methodological issues involved in research on the menstrual cycle: whether ovulation was determined using the LH surge or through a backward count method and whether analyses were performed on “cycles” or “participants.” We found no significant differences in the results of analyses performed using cycles with known LH surges versus cycles based on backward counts. Our overall conclusion is that the two methods of determining menstrual cycle phase yielded similar results. However, we also conclude that statistical power might be compromised when researchers use backward counts because the overall differences between the means were lower in these analyses than in those using LH surges. Therefore, studies with null research results, like those reported in Bellis and Meyers (2005), who not only used a backward count method but also retrospective data (participants were required to remember the date they started to menstruate), should be examined with caution. Furthermore, past studies that based their menstrual cycle phases on the LH surge consistently reported differences in women’s sexual desires and behavior prior to ovulation (Table 1). For example, Bullivant et al. (2004) reported increased sexual activity, libido, and sexual fantasies around ovulation, Graham et al. (2000) reported higher levels of sexual arousal in the periovulatory period, Haselton, Mortezaie, Pillsworth, Bleske-Rechek, and Frederick (2007) reported that women dressed better during their fertile phase, and our study found that women’s libido and sexual behavior increased prior to ovulation.
Similarly, we only found two significant differences when we analyzed data using cycles with LH surges versus data averaged across the participants’ scores. In the ANOVAs, we found a difference in autosexual behavior between the groups using cycles as data points but not when we averaged the participants’ data. We also found that positive affect was significantly related to autosex using averaged data but it failed to reach significance when we used the cycle data. All other findings were extremely similar across the two ways of handling the data.
Our results provide strong support for the hypothesis that, although women are receptive to sexual activity across their menstrual cycles, their sexual behavior and libido cluster at mid-cycle. First, we found that abstinent women reported increased libido and autosexual behavior at mid-cycle. The sexual behavior of abstinent women is less likely to be influenced by the sexual desires of others and therefore more likely to reflect the natural fluctuations in sexuality of women. Additionally, like previous researchers (Bullivant et al., 2004; Wilcox et al., 2004), we found that women, regardless of their sexual orientation, engaged in significantly more allosexual activity during their follicular and ovulatory phases with a second smaller peak pre-menstrually than at other times during the cycle. Therefore, it can be concluded that, although women exhibit continuous receptivity throughout their cycles, they have peaks in their sexual behavior before and during ovulation and again pre-menstrually.
We also found that emotions were related to women’s sexuality. Libido was related to positive affect. However, libido and positive affect varied in their relationship to allosexual behavior. Libido, after the effects of positive affect were partialled out, was positively related to allosexual behavior. However, positive affect, after the effects of libido were partialled out, was negatively related to allosexual behavior. These findings support theories such as Diamond’s (2003) that at least two systems are involved in women’s sexual behavior, one involving sexual arousal and related to mating behavior, and the other involving affection and related to attachment behavior. The fact that our results predict that sometimes libido will be positively related to sexual behavior while, at the same time, attraction is negatively related to sexual behavior helps explain the emotions and motivations behind findings like those of Haselton and Gangestad (2006). They found that women who were pair-bonded with men with low sexual attractiveness, relative to investment attractiveness, were more likely to report being attracted to other men when they were ovulatory (libido and affection acting independently) but were not attracted to other men outside of ovulation (libido and affection acting together). The peak in sexual behavior prior to menstruation is probably also related to pair-bonding.
Indeed, the physiological and brain scan literature supports the idea of two separate systems, one involving libido and the other involving pair-bond formation. Research indicates that reproductive hormones, like androgen and estrogen, are associated with libido (Fisher, Aron, Mashek, Li, & Brown, 2002), and fMRI studies find that the ventral striatum and hypothalamus are areas associated with intense sexual arousal (Walter et al., 2008). In contrast, pair-bonding most likely involves oxytocin and vasopressin (Fisher, Aron, & Brown, 2006) and the activation of the basal ganglia (Aron et al., 2005; Phan, Wager, Taylor, & Liberzon, 2002) and the cingulate cortex (Bartels & Zeki, 2004).
Autosexual behavior was positively related to both libido and the energetic/creative emotional factor and negatively related to positive affect. Both men and women reported engaging in more autosex after the sexual revolution in the 1960s (Dekker & Schmidt, 2002; Kontula & Haavio-Mannila, 2003). More research on autosexual behavior and its relationship to creativity and positive affect among individuals of varying sexual orientations needs to be conducted.
We thank Marci Arizumi, Louona Larkspur, Ariel Marsh, Lynn Morrison, Nicola Nicolaisen, Tiffany Freitas, Michelle McNamee, Sarah Asakawa, Aizelle Boado, and Lisa Oliver in helping to recruit the participants, and in data collection, organization, and analysis. This research was supported by NIH grant #S06-GM0873-33.