Objective: To provide estimates of normal variations in penile measurements and testicular volumes, and to establish reference ranges for clinical use.
Design: Cross-sectional, population-based study.
Setting: Schools, kindergartens, and child care centers in different parts of Bulgaria.
Participants: A population of 6200 clinically healthy white males aged 0 to 19 years.
Interventions: The study physician chose schools, kindergartens, and child care centers randomly and examined children at random until he reached the required number. Each of the 20 age groups (age range, 0-19 years) had an equal number of males (ie, 310).
Main outcome measures: The mean (SD) values and fifth, 50th, and 95th percentiles of height (Siber Hegner anthropometer), weight (beam balance), testicular volume (Prader orchidometer), penile length (rigid tape), and penile circumference (measuring tape) from birth to 19 years of age.
Results: Testes did not show any increase in size until the onset of puberty at age 11 years, whereas penile growth was gradual after birth. However, both penile and testicular development demonstrated peak growth from 12 to 16 years of age, which coincided with the maximal male pubertal growth spurt. Data indicate an earlier pubertal development for this study population than that for a similar population several decades ago. Significant differences between urban and rural populations regarding penile length were also noticed.
Conclusions: Our study provides the contemporary reference range values for height, weight, testicular volume, and penile length and circumference of males aged 0 to 19 years. Our data show that, even by the end of 20th century, there is still some acceleration of male pubertal development. For the first time are reported somatic differences in genitalia within a population between urban and rural representatives.