Obesity Is Strongly Associated With Low Testosterone and Reduced Penis Growth During Development

J Clin Endocrinol Metab. 2021 Oct 21;106(11):3151-3159. doi: 10.1210/clinem/dgab535.


Context: Growth of male genitalia represents an important marker of sexual development. Testicle size is the primary measure and little is known regards penile length changes during puberty.

Objective: This work aims to assess penis growth and testosterone levels in obese vs normal-weight children and adolescents, to evaluate a possible influence of obesity on genital development in boys, and to establish a new method for measuring penis length that allows comparison of normal-weight and overweight boys.

Methods: We assessed anthropometric and genital development in 1130 boys from birth to age 20 years. Testosterone levels were also measured. A new method for penile length measurement was employed to minimize errors when comparing obese and nonobese children. Penis length was measured with a gentle, painless, straight positioning on a centimetric ruler without stretching, which is doable from the first years of life until the end of adolescence.

Results: Penis length and testosterone are strongly related in children during puberty. Penile length growth is significantly decreased (by about 10%) in obese boys when compared to normal-weight boys, with concomitantly reduced testosterone levels, across puberal phases.

Conclusion: Childhood obesity represents an important determinant of lower testosterone level and reduced penis development. A new method should be employed to improve penis measurement in normal-weight and overweight/obese boys. The possible significance of these observations for adult genital development and reproductive potential will require large longitudinal studies.

Keywords: children; growth; measurements; obesity; penis; testosterone.

MeSH terms

  • Adolescent
  • Adult
  • Child
  • Child, Preschool
  • Cross-Sectional Studies
  • Endocrine System Diseases / blood
  • Endocrine System Diseases / epidemiology*
  • Follow-Up Studies
  • Humans
  • Infant
  • Infant, Newborn
  • Italy / epidemiology
  • Longitudinal Studies
  • Male
  • Pediatric Obesity / physiopathology*
  • Penis / growth & development
  • Penis / metabolism
  • Penis / pathology*
  • Prognosis
  • Testosterone / blood*
  • Young Adult


  • Testosterone