What clinician‑measured studies exist that report median penile length and girth, and can raw data be pooled to compute medians by region?
Executive summary
Clinician‑measured studies of penile length and girth exist across dozens of countries and several large pooled reviews, which typically report means (with SD/SE) rather than medians; a 2025 WHO‑region meta‑analysis and earlier global reviews summarize thousands of clinician‑measured observations but note major heterogeneity and regional data gaps [1] [2] [3]. Raw individual‑level data needed to compute true pooled medians by region are rarely published, and methodological differences in how length/girth were obtained (stretched vs erect, STT vs BTT, tape vs ruler, variable stretching force) materially limit straightforward pooling even when means are available [4] [5] [6].
1. What clinician‑measured studies and large datasets are available
Multiple clinician‑measured primary studies have been published from specific countries (for example large series from Italy with n≈4,685 men measured in urology clinics [7] [8], a US study of 1,661 sexually active men with staff‑measured erect parameters [9], and multicenter Argentine data reported in Asian Journal of Andrology [10] [11]); these feed into systematic reviews and meta‑analyses that aggregate tens of thousands of measurements [1] [3].
2. What the big meta‑analyses report (and what they don’t)
Recent systematic reviews/meta‑analyses present pooled means and standard errors for flaccid, stretched and erect length and for girth across WHO regions (for example pooled means: stretched length ≈12.84 cm, erect length ≈13.84 cm, flaccid circumference ≈9.10 cm, erect circumference ≈11.91 cm; and region‑specific means such as larger stretched length reported for the Americas) but these reports intentionally summarize means and SEs rather than medians, and the authors explicitly caution about heterogeneity, sparse data in regions like Africa and Southeast Asia, and sample non‑representativeness [1] [2] [6].
3. Why medians are rarely reported and why that matters
Primary clinician‑measured papers and the meta‑analyses commonly supply means and SD/SE because analytical conventions and available summary data favor those metrics [5] [3]. Medians require either original individual‑level data or studies that publish median and interquartile ranges; such reports are uncommon in the literature cited, so producing robust pooled medians by region from published summaries alone is generally not possible without making distributional assumptions that can mislead given skew or multimodality [1] [3].
4. Can raw data be pooled to compute medians by region?
In principle, yes—if investigators share participant‑level datasets (age, measurement technique, BTT/STT, erect vs stretched, country/region)—true pooled medians and region‑specific medians can be computed. In practice, most source material in the cited meta‑analyses consists of published summary statistics, not individual raw data, making direct pooling infeasible; even where large national datasets exist (Italy, USA, Argentina), they are not uniformly available in raw form for re‑analysis in public repositories referenced by the reviews [7] [8] [9] [10] [1].
5. Methodological and interpretive caveats that block simple pooling
Measurement technique variation (site of circumference measurement, bone‑to‑tip vs skin‑to‑tip, stretched force, temperature, participant selection and ability to achieve erection) introduces systematic differences between studies that can shift means and medians; for example stretched‑length methods depend on clinician‑applied force and studies have measured variability in required and applied stretching forces [5], while andrology‑center protocols show detailed but non‑identical measurement procedures [4]. Meta‑analysts therefore must adjust or stratify by technique—an often imperfect workaround—and authors repeatedly warn about heterogeneity and regional sample bias [6] [2].
6. Bottom line for researchers or clinicians wanting medians by region
Existing clinician‑measured studies and meta‑analyses provide robust pooled mean estimates and large national datasets exist, but true pooled medians by WHO region require access to original participant‑level data or more primary studies that publish medians/IQRs; absent that, any attempt to substitute medians from means requires explicit assumptions and will inherit the substantial methodological heterogeneity documented across sources [1] [2] [4]. Industry or marketing summaries that promote single‑number “averages” should be treated skeptically because they often mix self‑reported and clinician‑measured data and can bias perceptions [12].