I'm reading some urology papers and came across one involving penis growth (Kim & Song, 2008); here's an intro passage that I'm confused about:
A total of 58 patients with constitutionally small penises, without chromosomal anomalies and gene-associated syndromes, intersex, and hypospadias, were included in this study. The average patient age at their first visits was 10 years and the average follow-up period was 2.2 years.
What's a "constitutionally small penis"?
I've read the paper in detail and I don't see where the authors distinguish between a small penis and a "constitutionally small" penis.
Would a "constitutionally small penis" be the same thing as a "micro-penis"? If not, then where do we draw the line?
Kim, K. S., & Song, G. G. (2008). Penile Growth After Puberty in Patients with a Constitutionally Small Penis. Journal of Pediatric Urology, 4, S63. doi: 10.1016/j.jpurol.2008.01.174
"Constitutional" refers to the physical state of the concerned individual (Merriam-Webster).
In biology, it most probably means a trait that is not pathological or environment induced.
This is in the context of size of babies:
Small for gestational age (SGA) can occur following a pathological process or may represent constitutionally small fetuses.
From: Ananth & Vintzileos (2009)
Between18-22% of infants SGA by population standards are reclassified as normally grown by customized standards and as the perinatal mortality of these reclassified babies is similar to those who are normally grown they can be considered to be "constitutionally small.".
From: McCowan et al. (2018)
In most cases, it is difficult to differentiate between constitutionally small head size vs pathologic microcephaly, and available data regarding prenatal diagnosis of microcephaly are based on small numbers of cases of varying etiologies.
From: Ultrasound screening for fetal microcephaly following Zika virus exposure. American Journal of Obstetrics & Gynecology, Volume 214, Issue 6, B2 - B4
Regarding constitutionally small penis: Since the article you mentioned is the only source (scientific or otherwise) of this term, I would believe that it is based on the population average (of possibly South Korea from where the authors are). Moreover, since it is not defined rigorously, it is most likely an arbitrary classification.