Relation Between Penis Size and Gender of Baby

Korean J Urol. 2015 Mar; 56(3): 248–253.

Penile length, digit length, and anogenital distance according to nativity weight in newborn male infants

Jae Immature Park

Section of Urology, Ulsan University Hospital, University of Ulsan Higher of Medicine, Ulsan, Korea.

Gina Lim

¹Department of Pediatrics, Ulsan University Infirmary, University of Ulsan College of Medicine, Ulsan, Korea.

Ki Won Oh

^oneSection of Pediatrics, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.

Dong Soo Ryu

²Section of Urology, Samsung Changwon Hospital, Sungkyunkwan Academy School of Medicine, Changwon, Korea.

Seonghun Park

ⁱⁱⁱSchool of Mechanical Technology, Pusan National University, Busan, Korea.

Jong Chul Jeon

Section of Urology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.

Sang Hyeon Cheon

Department of Urology, Ulsan University Infirmary, University of Ulsan Higher of Medicine, Ulsan, Korea.

Kyung Hyun Moon

Section of Urology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.

Sejun Park

Department of Urology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.

Sungchan Park

Department of Urology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.

Received 2015 Jan viii; Accepted 2015 February vi.

Abstract

Purpose

Anogential distance (AGD) and the 2:4 digit length ratio announced to provide a reliable guide to fetal androgen exposure. Nosotros intended to investigate the current status of penile size and the human relationship betwixt penile length and AGD or digit length according to birth weight in Korean newborn infants.

Materials and Methods

Between May 2013 and Feb 2014, among a total of 78 newborn male infants, 55 infants were prospectively included in this study. Newborn male infants with a gestational historic period of 38 to 42 weeks and birth weight>2.5 kg were assigned to the NW group (n=24) and those with a gestational age<38 weeks and birth weight<ii.five kg were assigned to the LW group (northward=31). Penile size and other variables were compared between the ii groups.

Results

Stretched penile length of the NW group was iii.3±0.2 cm, which did not differ significantly from that reported in 1987. All parameters including height, weight, penile length, testicular size, AGD, and digit length were significantly lower in the LW group than in the NW group. Nonetheless, there were no meaning differences in AGD ratio or two:4 digit length ratio betwixt the 2 groups.

Conclusions

The penile length of newborn infants has not changed over the last quarter century in Korea. With normal penile advent, the AGD ratio and two:4 digit length ratio are consistent irrespective of nativity weight, whereas AGD, digit length, and penile length are significantly smaller in newborns with low birth weight.

Keywords: Anthropometry, Newborn infants, Penis

INTRODUCTION

Scarce androgen exposure during fetal masculinization results in smaller sized testes, prostate, seminal vesicles, and penis in adulthood and is associated with an increased risk of hypospadias and lower testosterone levels [1,2,3,4]. Information technology is well established that normal penile development is dependent on testosterone, its conversion via steroid 5-alpha-reductase to dihydrotestosterone, and a functional androgen receptor [5]. Penile length increases slowly until iv years of historic period, after which follows a steady phase and so a rapid increment with puberty. Androgen deficiency is likewise known to exist associated with a reduction in anogenital altitude (AGD) in adults [6], and information technology is postulated that the ratio of the second to the fourth finger length (2:four digit ratio) in adult men reflects fetal androgen exposure [7].

Studies on penile length in newborns have been very rarely conducted, especially in Korea. In 1987, a study on penile length and testicular size was conducted with 1,071 Korean children including 49 newborn infants [8]. In newborns, the hateful and standard deviation (SD) of stretched penile length (SPL) was 3.3±0.5 cm. Early diagnosis of abnormalities in penile size is important both medically and psychologically [9]. The exact penile size is a near important factor in diagnosing penile problems such equally micropenis, which is defined as an SPL<2.five SDs below the mean for age with normal office and construction [10].

Until now, no reports accept addressed penile length according to birth weight and its relationship with birth weight and AGD or digit length in newborn infants. This study was preliminarily performed to update the normal SPL values that can be used for Korean newborns. We also intended to investigate the current condition of penile length and the human relationship of penile length with AGD or digit length according to nascency weight in Korean newborn infants.

MATERIALS AND METHODS

1. Patient characteristics

This cross-exclusive report was performed in the neonatal unit of our establishment between May and Jan 2014. Of a total of 78 newborn male infants, 55 infants were prospectively enrolled in this written report. Exclusion criteria were penile diseases, including hypospadias, curtained penis, cryptorchidism, and varicocele, and other growth issues such as chronic renal failure and endocrinologic disorders [11]. Therefore, most newborn infants who were considered to be normal and healthy except for their nascence weights were included in the current study. The infants were divided into two groups. The normal weight group included newborns with a gestational historic period of 38 to 42 weeks and birth weight≥2.5 kg (NW, n=24). The low birth weight group included newborns with gestational historic period<38 weeks and nascency weight<2.5 kg (LW, n=31).

two. SPL and variables

The penile length was measured every bit the SPL. The length was measured twice for each babe and the mean of the ii measurements was recorded. The SPL was measured with a ruler past compressing the fat tissue with ane finish of the ruler through the pubic ramus; and then the penis was fully stretched and the distance to the glans of the stretched penis was plotted [11]. None of the 55 infants had been circumcised. Foreskins of the uncircumcised infants were not involved in the measurement. Testicular size was measured by using Prader orchidometry (mL). Genital distances were measured with the male infant in a supine and frog-leg position [12]. AGD1 was the distance from the anterior aspect of the penis to the anal verge (Fig. 1A). AGD2 was the distance from the posterior aspect of the penis to the anal verge. AGD3 was the distance from the posterior aspect of the scrotum to the anal verge every bit measured by use of a caliper [xiii]. Digit lengths were measured past using a ruler on the left manus. Digit lengths were measured twice for each baby and the mean of the 2 measurements was recorded. The measurement was taken from the basal crease to the tip on the ventral surface of the hand at a indicate midway beyond a line perpendicular to the base past using rulers (Fig. 1B).

Measurement of anogenital distance (AGD) and 2:4 digit lengths. (A) AGD has been measured in three ways (AGD1, AGD2, AGD3), AGD3 appears to be the nearly reliable and repeatable measurement. (B) Digit lengths is measured course the basal crease to the tip on the ventral surface of the hand at the point midway beyond a line perpendicular to the base using rulers.

For all infants, age, SPL, acme, body weight, testicular size, digit lengths of the second and fourth fingers and the ratio between them, and AGDs and their ratios were measured. Penile size and other variables were also compared between the 2 groups.

three. Interobserver variability

SPL was measured in 55 infants by 2 observers (an urologist and a pediatric doctor) to gauge interobserver difference. Differences in the measurements of penile length were evaluated by using paired t-tests for the LW group and Wilcoxon's signed rank test for the NW group.

4. Statistical assay and ethics argument

Data analysis was performed by using the software package SPSS ver. 17.0 (SPSS Inc., Chicago, IL, USA). Continuous variables were expressed as the hateful±SD. Differences in SPL, superlative, trunk weight, and testicular size between the study in 1987 and the current study were evaluated by Student t-exam. Variables in the NW and LW groups were compared past Mann-Whitney U test. A p-value of <0.05 was accepted to be statistically significant.

This study was approved by the Institutional Review Board of Ulsan University Hospital (IRB No. 2013028). Clinical information were prospectively collected and the medical records of all the participants were reviewed.

RESULTS

ane. SPL compared with the previous report (1987)

The SPL of the NW group (n=24, >two.5 kg) was three.3±0.2 cm. Compared with the previous study results reported in 1987, there was no significant change in the SPL (p=0.445). Among the anthropometric measurements of Korean children, in that location was a significant decrease in tiptop (49.8±1.9 cm), whereas at that place were no significant changes in body weight (3.2±0.5 kg) or testicular size (1.1±0.four mL) (Table one).

Table 1

Changes in stretched penile length and anthropometric data compared with a previous written report conducted in 1987

Variable	Present data (north=24)	1987 Information (n=49)	p-value
Penile size (cm)	3.iii±0.2	three.three±0.5	0.445
Testis size (mL )	ane.one±0.4	one.2±0.2	0.248
Summit (cm)	49.8±1.ix	52.v±2.5	<0.001
Weight (kg)	3.2±0.5	three.3±0.4	0.393

2. Penile length, digit length, and AGD according to birth weight

The SPLs of the NW and LW groups were 3.3±0.two cm and ii.9±0.iv cm, respectively (p<0.001). All parameters including height, weight, penile length, testicular size, AGD1-iii, and the length of the 2d and 4th fingers were significantly lower in the LW group than in the NW group. Still, there were no significant differences in the AGD ratio or in the 2:4 digit length ratio betwixt the two groups (Table two).

Table 2

Differences in penile length, digit lengths, anogenital distances, and anthropometric data according to nascency weight

Variable	Normal birth weight group (n=24)	Depression birth weight group (n=31)	p-value
Penile size (cm)	3.three±0.2	2.9±0.iv	<0.001
Testis size (mL )	1.1±0.4	0.8±0.four	<0.001
Height (cm)	49.eight±1.9	44.ane±two.ix	<0.001
Weight (kg)	3.2±0.5	2.1±0.iv	0.006
SPL/peak (×ten-2)	6.nine±0.5	6.3±0.4	<0.001
Digit 2 (cm)	2.6±0.2	2.2±0.2	<0.001
Digit 4 (cm)	2.eight±0.iii	2.four±0.2	<0.001
Digit 2/4 ratio	0.92±0.03	0.93±0.05	0.419
AGD anea (cm)	iv.2±0.3	iii.6±0.four	<0.001
AGD 2b (cm)	3.5±0.iii	iii.1±0.3	<0.001
AGD 3c (cm)	2.iii±0.2	ii.0±0.ii	<0.001
AGD iii/height (×10-ii)	4.8± 0.5	4.half dozen±0.4	0.056
AGD one-three (cm)	1.viii±0.three	1.half-dozen±0.3	<0.001
AGD 1-two (cm)	0.half-dozen±0.one	0.5±0.1	0.003
AGD (ane-2)/(ane-3) ratio	0.35±0.05	0.34±0.05	0.478

three. Interobserver variability in penile length

In the NW group, there was no significant difference in SPL between two observers (3.3±0.ii cm and three.two±0.iii cm, p=0.165); however, at that place was a significant departure between two observers in the LW grouping (2.ix±0.four cm and two.7±0.iv cm, p=0.001).

DISCUSSION

The penile length in children has increased significantly [11]; nonetheless, the penile length of newborn infants has not changed over the last quarter century. Biological and environmental changes and changes in feeding patterns during the rapid economical growth since 1987 may have affected the growth and development of the human body. The height and weight of Korean children have increased significantly compared with 1987 [11]. Even so, according to the current study results, there has been no significant change in the nascence weight of newborn infants, whereas there has been a reduction in their heights compared with 1987. It may be that Korean mothers today intentionally keep fetal weight under control for a safety and problem-free delivery. The exact causes of the decreased height for infants are unknown and must be evaluated in the future. There is no apparent relationship betwixt gestational age and penile length at 37 to 42 weeks [fourteen]. Therefore, we compared the current data with similar data reported in 1987 for a gestational age of 38 to 42 weeks and birth weight≥ ii.5 kg. Although the 2 studies were conducted in geographically different places, one in Ulsan and the other in Seoul in Korea (1987), and penile length was measured by different individuals, both studies were conducted with Korean populations and penile length was measured past the SPL technique.

In humans, AGD differs by sex; boys have a longer AGD than do girls [15]. Additionally, numerous studies accept shown sexual activity differences in the 2:4 digit length ratio, and males accept a lower 2:4 digit length ratio than do females [16]. Longer male AGD may be determined by an androgen event during the presumptive masculinization programming window before 11 to xiii weeks of gestation as in rodents [ane]. No formal studies accept however reported AGD in patients with consummate androgen insensitivity, which would provide definitive proof that fetal androgens make up one's mind the longer AGD in human males [13]. However, a written report conducted with Caucasian infants reported a significant reduction in AGD in boys with hypospadias (42 control and 77 infants with hypospadias, p=0.002) [17]. In another report conducted with 116 adults, a significant positive correlation between AGD and testosterone levels was demonstrated [6].

Some bug with AGD measurement need to exist resolved. AGD3 is the distance from the posterior aspect of the scrotum to the anal verge. AGD3 is besides called the anoscrotal distance and appears to be the most reliable and repeatable measurement [fifteen,18]. In the current study, AGD1, 2, and iii were measured as the reference to apply bones epidemiologic data [13].

There is as well some conflict as to which hand presents the about sexually unlike 2:four digit length ratio. At birth, sex difference in the 2:4 digit length ratio is pregnant only for the left hand [nineteen]. In the current report, nosotros measured digit length for the 2d and fourth fingers on the left mitt. The largest study to date, which included 360 young men from a normal population, found no relationship of 2:four digit length ratio with testis or semen parameters [20]. Other studies showed pregnant negative associations between 2:iv digit length in men and reproductive success; in those studies, the 2:four digit length ratio was college in infertile men than in fertile men [21,22]. There are no reports on the relationship between the 2:4 digit length ratio and the occurrence of cryptorchidism or hypospadias.

Until now, there has been no report regarding the relationship between birth weight and AGD or digit length in newborn infants. Nosotros thus intended to investigate these variables. In the current study, all parameters including height, weight, penile length, testicular size, AGD1-3, and the length of the 2d and fourth fingers were significantly lower in the LW group than in the NW group. The difference may take been caused by a difference in total body size. In the current report, we excluded newborn infants with hypospadias, concealed penis, cryptorchidism, varicocele, and other growth problems such as chronic renal failure or endocrinologic disorders. Nosotros thus assumed that the testosterone exposure of the subjects in this study was at a normal level. The electric current study results suggested that birth weight is not associated with the AGD ratio or with the 2:four digit length ratio. In terms of interobserver variability, there was no divergence in newborn males with normal birth weight between the raters. Nevertheless, interobserver variability cannot be completely excluded in the LW grouping. It is possible that in that location may have been a divergence according to the fourth dimension of measurement of penile length of newborn males [14]. The penile length measured within 12 hours after birth was 0.31 cm shorter than that remeasured at ane to 7 days of age in 63 infants.

CONCLUSIONS

The penile length in children has increased significantly, whereas that in newborn infants has not inverse over the terminal quarter century in Korea. With a normal penile appearance, the AGD ratio and the 2:iv digit length ratio are consistent irrespective of birth weight, whereas the AGD, digit length, and penile length are significantly smaller in newborns with low birth weight. It is possible that the departure in penile length may have resulted from interobserver variability.

ACKNOWLEDGMENTS

This work was supported by the Priority Research Center Program through the National Enquiry Foundation of Korea (NRF) funded past the Ministry building of Teaching, Scientific discipline and Technology (2009-0094050).

Footnotes

The authors take nothing to disclose.

References

i. Welsh G, Saunders PT, Fisken M, Scott HM, Hutchison GR, Smith LB, et al. Identification in rats of a programming window for reproductive tract masculinization, disruption of which leads to hypospadias and cryptorchidism. J Clin Invest. 2008;118:1479–1490. [PMC free commodity] [PubMed] [Google Scholar]

two. Macleod DJ, Sharpe RM, Welsh M, Fisken M, Scott HM, Hutchison GR, et al. Androgen action in the masculinization programming window and development of male reproductive organs. Int J Androl. 2010;33:279–287. [PubMed] [Google Scholar]

3. van den Driesche S, Scott HM, MacLeod DJ, Fisken M, Walker M, Sharpe RM. Relative importance of prenatal and postnatal androgen activeness in determining growth of the penis and anogenital distance in the rat before, during and after puberty. Int J Androl. 2011;34(6 Pt 2):e578–e586. [PubMed] [Google Scholar]

iv. Drake AJ, van den Driesche Due south, Scott HM, Hutchison GR, Seckl JR, Sharpe RM. Glucocorticoids amplify dibutyl phthalate-induced disruption of testosterone production and male reproductive development. Endocrinology. 2009;150:5055–5064. [PubMed] [Google Scholar]

5. Kim KS, Liu W, Cunha GR, Russell DW, Huang H, Shapiro E, et al. Expression of the androgen receptor and v alpha-reductase type 2 in the developing human fetal penis and urethra. Jail cell Tissue Res. 2002;307:145–153. [PubMed] [Google Scholar]

6. Eisenberg ML, Jensen TK, Walters RC, Skakkebaek NE, Lipshultz LI. The relationship betwixt anogenital distance and reproductive hormone levels in adult men. J Urol. 2012;187:594–598. [PubMed] [Google Scholar]

seven. Buck JJ, Williams RM, Hughes IA, Acerini CL. In-utero androgen exposure and 2d to fourth digit length ratio-comparisons betwixt healthy controls and females with classical congenital adrenal hyperplasia. Hum Reprod. 2003;18:976–979. [PubMed] [Google Scholar]

8. Chung KH, Choi H, Kim SW. Penile and testicular sizes of Korean children. Korean J Urol. 1987;28:255–258. [Google Scholar]

10. Tsang Southward. When size matters: a clinical review of pathological micropenis. J Pediatr Health Care. 2010;24:231–240. [PubMed] [Google Scholar]

eleven. Lee JH, Ji YH, Lee SK, Hwang HH, Ryu DS, Kim KS, et al. Change in penile length in children: preliminary study. Korean J Urol. 2012;53:870–874. [PMC free article] [PubMed] [Google Scholar]

12. Kim TH, Lee HH. Anogenital altitude in newborns. Reprod Biomed Online. 2014;29:771. [PubMed] [Google Scholar]

thirteen. Dean A, Sharpe RM. Clinical review: anogenital distance or digit length ratio as measures of fetal androgen exposure: human relationship to male reproductive development and its disorders. J Clin Endocrinol Metab. 2013;98:2230–2238. [PubMed] [Google Scholar]

14. Matsuo N, Ishii T, Takayama JI, Miwa One thousand, Hasegawa T. Reference standard of penile size and prevalence of buried penis in Japanese newborn male infants. Endocr J. 2014;61:849–853. [PubMed] [Google Scholar]

15. Thankamony A, Ong KK, Dunger DB, Acerini CL, Hughes IA. Anogenital distance from nativity to 2 years: a population report. Environ Health Perspect. 2009;117:1786–1790. [PMC gratis article] [PubMed] [Google Scholar]

16. Manning JT. Digit ratio (2d:4D), sex differences, allometry, and finger length of 12-30-year olds: evidence from the British Broadcasting Corporation (BBC) Cyberspace report. Am J Hum Biol. 2010;22:604–608. [PubMed] [Google Scholar]

17. Salazar-Martinez Eastward, Romano-Riquer P, Yanez-Marquez Eastward, Longnecker MP, Hernandez-Avila Yard. Anogenital distance in human male and female person newborns: a descriptive, cross-sectional study. Environ Health. 2004;3:8. [PMC free commodity] [PubMed] [Google Scholar]

18. Swan SH, Main KM, Liu F, Stewart SL, Kruse RL, Calafat AM, et al. Subtract in anogenital distance amidst male infants with prenatal phthalate exposure. Environ Health Perspect. 2005;113:1056–1061. [PMC gratuitous article] [PubMed] [Google Scholar]

xix. Ventura T, Gomes MC, Pita A, Neto MT, Taylor A. Digit ratio (2D:4D) in newborns: influences of prenatal testosterone and maternal environment. Early Hum Dev. 2013;89:107–112. [PubMed] [Google Scholar]

20. Lu H, Huo ZH, Liu YJ, Shi ZY, Zhao JL. Correlations between digit ratio and infertility in Chinese men. Early Hum Dev. 2012;88:865–869. [PubMed] [Google Scholar]

21. Manning JT, Barley L, Walton J, Lewis-Jones DI, Trivers RL, Singh D, et al. The 2nd:4th digit ratio, sexual dimorphism, population differences, and reproductive success. bear witness for sexually antagonistic genes. Evol Hum Behav. 2000;21:163–183. [PubMed] [Google Scholar]

22. Auger J, Eustache F. Second to fourth digit ratios, male person genital development and reproductive health: a clinical study among fertile men and testis cancer patients. Int J Androl. 2011;34(4 Pt two):e49–e58. [PubMed] [Google Scholar]

Relation Between Penis Size and Gender of Baby

Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4355437/

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