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Background

Bondage/discipline, Dominance/submission, sadism/masochism

Distinct differences between D/s identities

Testosterone, helps determine sex in utero

↑T associated with

↑dominance
↑risk-taking
↑sensation-seeking

Smaller 2D:4D ratio = more T

Larger 2D:4D ratio = less T

Very briefly, BDSM or, Bondage and Discipline, Dominance and Submission, Sadism and Masochism is a consensual practice that involves role-playing, power dynamics, and sexual fetishes. Power play (or the D/s element bolded on the slide) is often negotiated and agreed upon before engaging in BDSM activities and often involves one partner assuming a dominant role while the other(s) assume a submissive role and defer to the Dominant’s commands.

Now for some individuals, their power play role is not simply a leisurely sexual activity, but rather stable over time and across situations and partners. In fact, some BDSMers state that their role as a Dominant or submissive is a part of their identity. This identity piece is what my research is mostly interested in.

While in utero, the developing fetus is exposed to prenatal androgens, like testosterone, that assist in determining the sex of the child. Prenatal testosterone seems to play a role in gender development and gender expression as well.

Research has found that higher levels of testosterone are associated with several personality factors as well as behaviors related to dominance, aggression, risk-taking, and sensation-seeking. Now you’re catching my drift!

(plus) Levels of prenatal T also influence the second to fourth digit (2D:4D) ratio. The ratio is calculated by measuring the lengths of the index and ring fingers and dividing the length of the index by the ring finger.

Now before you start looking at your hands, listen carefully. Higher levels of androgen exposure are associated with a smaller 2D:4D ratio, indicating a more “masculine” pattern. That is, the second finger is typically relatively longer and the fourth finger is shorter. Conversely, lower levels of androgen exposure are related to a larger 2D:4D ratio.

These studies collectively suggest that other psychological and/or biological mechanisms may influence preference, and thus identity, in BDSM and power play. Hence the present study aims. I predicted that there would be differences in prenatal T, as measured by 2D:4D ratio, between genders and power players, as well as an interaction of the two.

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Moreover, 2D:4D may function as a predictor of these individual differences, such that differences in testosterone might predict power players’ preferred roles.

The present study thus sought to determine the extent to which prenatal hormones via 2D:4D ratio, impact BDSM power play role preference and related personality factors

***It is important to note that Levels of hormones during puberty and socialization also play a role in gender identity beyond just prenatal androgen.***

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Method

Dominant and submissives (only) recruited online and at events

Eligibility survey (~ 5min)

Second survey with questionnaires (~20 min)

Domain-Specific Risk-Taking scale (Blais & Weber, 2006)
Nonsexual Experience Seeking Scale (Kalichman et al., 1994)
Sexual Sensation-Seeking scale (Gaither & Sellbom, 2003)

Hand scans, measured later using GIMP

Dominant and submissive self-identifying individuals were recruited in various ways, but a majority of our participants were recruited at BDSM or Pride events via tabling methods.

Depending on the recruitment method and order of operations, participants completed a short eligibility survey, a longer survey with several personality questionnaires, and scanned their hands using a photocopier.

Then the software GIMP was used to precisely measure the distance from the basal creases to the tips the fingers on both hands.

The Domain-Specific Risk-Taking scale, or DOSPERT (Blais & Weber, 2006), was used to evaluate the likelihood with which respondents might engage in risky behaviors.

The Nonsexual Experience Seeking scale derived from the same parent scale (Zuckerman et al. 1964) as the SSSS, but pertains to nonsexual activities.

The sexual sensation-seeking scale (SSSS; Gaither & Sellbom, 2010) asked participants to rank statements concerning their stance on sexual behavior.

Demographic questions

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Results

N= 250 adult BDSM D/s power players

Majority White, gay, submissive, men, ~37.7, 14.6% transgender

H1: Men T > Women T

H2A: Dominant T > submissive T

H2B: No interaction

covariates: handedness, # siblings, race, (gender)

H3: ↑T ↑risk-taking

Dominant submissive

in Total, there were 250 participants after data cleaning. You can see a bit of the demographic information here. 14.6 % transgender.

H1: GENDER DIFFERENCES (independent sample t-test followed by an ANCOVA with race, siblings, and handedness as covariates)

SIGNIFICANT difference between men and women regarding right and left hand digit ratios, with men showing smaller 2D:4D ratios (more T) than women

Note that this statistic includes transgender participants. In a sample of cisgender people (N=156) the effect was stronger for both right and left hands.

When covariates were included in the model, there was still a significant difference in digit ratio between men and women on the right hand.

H2A: POWER ROLE DIFFERENCES

SIGNIFICANT difference between Dominant and submissive roles on the right hand, but not the left. So Dominants had smaller ratios than submissives.

When covariates, including gender, were included in the model, the effect remained significant

In a sample of cisgender people, the effect was also stronger for right hand (p<.001) but nonsig for left hand

H2B: INTERACTION BETWEEN GENDER AND POWER ROLE (two-way ANCOVA with race, siblings, and handedness as covariates)

No significant interaction between gender and power role.

With covariates in the model, the interaction still wasn't significant (probably due to low power).

H3: RELATIONSHIP BETWEEN 2D:4D RATIO AND RISK-TAKING AND SENSATION-SEEKING (Pearson bivariate correlations)

Right hand digit ratio was significantly, negatively correlated with financial risk (r= -.12), health risk (r= -.15), and total risk (r= -.12), but nothing for sensation-seeking. Thus, exposure to more prenatal T is related to increased risk-taking attitudes.

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EXTRA:�The specific hypotheses are as follows:

1. GENDER DIFFERENCES: Higher levels of prenatal testosterone (lower 2D:4D ratio) will be more common among men, whereas lower levels of prenatal testosterone (higher 2D:4D ratio) will be more common among women.

2a. POWER ROLE DIFFERENCES: Dominant roles will exhibit ↑T (lower 2D:4D ratio) whereas submissives will exhibit ↓T (higher 2D:4D ratio).

2b. INTERACTION (X): Dominant men will have lower ratios than submissive men, Dominant women will have lower ratios than submissive women, and Dominant men will have lower ratios than Dominant women.

3. Levels of prenatal testosterone will negatively correlate with personality traits. Specifically, lower 2D:4D ratios will be associated with significantly higher sensation-seeking and risk-taking, relative to higher 2D:4D ratios.

DEMOGRAPHICS: Mean age 37.77 (SD=12.47) with most participants falling in the age range between 25-34, 55.2% submissive identified, 46% experienced frequently practice BDSM, 84.8% right-handed, 34.9% bachelor’s degree, 22.5% income $50,000 through $74,000, 87.7% White, 91.5% as Not Hispanic/Latine, 14.6% transgender, 53.3% men, 28.4% gay, 28% homoromantic, 37% polyamorous/ENM, 28.3% currently in a polyamorous relationship.�

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Discussion & Implications

Distinct differences in T based on gender and D/s power role

Emphasis on Right hand

Psychological and biological markers of BDSM and power play preferences

Support sexual diversity and legitimize BDSM identification

Inclusive and tailored care, policy protections

So yay, Several hypotheses were supported!

Significant differences were predominantly found on the right hand, aligning with prior research that consistently reports stronger right-hand effects.

Overall, these results suggest underlying biological and psychological differences between BDSM power play roles! The findings from the present study may help distinguish the BDSM community as biologically distinct in measurable ways, which can contribute to broader recognition of its legitimacy. Although digit ratio alone does not determine identity or behavior, consistent physiological patterns can support arguments that this population is not simply defined by social or environmental factors. Such evidence may strengthen calls for inclusive health care practices, tailored mental health support, and policy protections by reinforcing the validity of community members’ identities.

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We need more studies on how testosterone relates to personality and sexual behavior in underrepresented populations like BDSM practitioners. Understanding prenatal testosterone differences among diverse sexualities on a bigger scale could help support protections against discrimination.

As visibility of the BDSM community grows, it is important for researchers, clinicians, and policy-makers to understand and address the rights and privileges of people who practice BDSM.

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EXTRA:

This study encountered some limitations.

We didn’t include people who identify as switches. Although this helped reduce ambiguity, it also left out a lot of people whose experiences are central to the community. Relatedly, some individuals who expressed interest mentioned that they were switches, but leaned towards Dominance or leaned submissive. Thus, in the future, a sliding-scale or continuum could capture that nuance better than fixed categories (which is what we had).
Relatedly, some participants identified as “bottom doms” or “submissive tops,” showing that dominance/submission and sexual position are independent dimensions, especially among gay men. As such, confusion over eligibility may have affected participation and sample size.
Factors such as height, weight, and congenital adrenal hyperplasia (CAH) were not controlled for, which may influence results.
Stigma and fear of exposure made some individuals hesitant to participate. Expressed concerns about privacy, data misuse, and mistrust of institutions (especially in light of the current administration) may have also reduced participation.
Finally, Online participants had to scan and email their hands, was a barrier to participation. We had several participants recruited from events who didn’t finish the study either, even with reminder emails. Thus, issues with attrition definitely impacted our final sample size.