Evidence map›Paper›PMID 42289270›Full record

SynthesisBJU international2026

Paediatric penile length: a systematic review and meta-analysis.

Fausto Negri, Federico Belladelli, Chiyuan A Zhang, James Stinson, Ashkan P Langroudi, Satvir S Basran, Abby L Chen, Edoardo Pozzi, Yu-Sheng Cheng, Francesco Del Giudice and 3 more

Abstract readSystematic ReviewMeta-AnalysisReview
In one paragraph

Synthesis in BJU international, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

13 authors.

Fausto NegriDepartment of Urology, School of Medicine, Stanford University, Stanford, CA, USA.ORCID 0000-0002-3677-6412
Federico BelladelliDivision of Experimental Oncology/Unit of Urology, URI; IRCCS Ospedale San Raffaele, Milan, Italy.ORCID 0000-0002-2165-659X
Chiyuan A ZhangDepartment of Urology, School of Medicine, Stanford University, Stanford, CA, USA.
James StinsonDepartment of Urology, School of Medicine, Stanford University, Stanford, CA, USA.
Ashkan P LangroudiDepartment of Urology, School of Medicine, Stanford University, Stanford, CA, USA.
Satvir S BasranDepartment of Urology, School of Medicine, Stanford University, Stanford, CA, USA.
Abby L ChenDepartment of Urology, School of Medicine, Stanford University, Stanford, CA, USA.
Edoardo PozziDivision of Experimental Oncology/Unit of Urology, URI; IRCCS Ospedale San Raffaele, Milan, Italy.ORCID 0000-0002-0228-7039
Yu-Sheng ChengDepartment of Urology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Francesco Del GiudiceDepartment of Maternal, Infant and Urologic Sciences, Policlinico Umberto I Hospital, 'Sapienza' University of Rome, Rome, Italy.
Francesco MontorsiDivision of Experimental Oncology/Unit of Urology, URI; IRCCS Ospedale San Raffaele, Milan, Italy.
Andrea SaloniaDivision of Experimental Oncology/Unit of Urology, URI; IRCCS Ospedale San Raffaele, Milan, Italy.ORCID 0000-0002-0595-7165
Michael L EisenbergDepartment of Urology, School of Medicine, Stanford University, Stanford, CA, USA.ORCID 0000-0001-5482-0141

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

objectiveTo assess geographical variation in stretched penile length among prepubertal boys and evaluate temporal trends over the past two decades, as defining reference values for genital organ size remains crucial for early identification of development disorders.

methodsThe PubMed, Cochrane and Scopus databases (no deadlines for publishing were imposed) were searched according to the Preferred Reporting Items for Systematic Review and Meta-analyses statement. Five authors independently extracted individual participant data and assessed the risk of bias. Studies with quantitative penile lengths were included; those involving congenital malformations were excluded. The review protocol was prospectively registered in the International Prospective Register of Systematic Reviews (registration number CRD42022335643).

resultsA total of 55 studies from 2000 to 2024 were evaluated, including data from 31 915 boys. Pooled mean stretched penile length estimates were 3.07 cm (95% confidence interval [CI] 2.88-3.26 cm) for the 1-week-old boys, 3.73 cm (95% CI 3.53-3.93 cm) for the 1-year-old boys, 4.69 cm (95% CI 4.49-4.88 cm) for the 2-5 year-old boys, and 5.43 cm (95% CI 5.20-5.66 cm) for the 5-10 year- old boys. When comparing data from the 2000s to the 2020s, stretched penile length decreased by 16.2% (from 3.46 to 2.90 cm), 16.3% (from 4.17 to 3.49 cm), 21.5% (from 5.31 to 4.17) and 26.2% (from 6.46 to 4.77 cm) in the 1-week-old, 1-year-old, 2-5-year-old and 5-10-year-old boys, respectively. Subgroup analysis for those aged >2 years showed significant variations by geographical region (P < 0.001).

conclusionsThe present study observed large variations in penile length across geographical regions and among prepubescent boys of different ages, while also suggesting a possible decline over the past two decades.

Indexed as

PenisChildChild, PreschoolHumansInfantMaleOrgan SizeReference Valuesgenitaliapaediatricspenisreference valuessex development

Identifiers

PMID42289270
PMCPMC13550798

What OpenQuestion holds

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.