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penis. Therefore, accurate measurement of stretched penile length should be
done prior to subjecting a child for evaluation of micropenis. The stretched
penile length of the child was 5 cm, which was within 2.5 SD for his age, and
therefore, parents were reassured. The normative data for stretched penile
length at various ages and cutoff for the diagnosis of micropenis are given in
the table below.Age Mean ± SD (cm)Micropenis
(Mean-2.5 SD, cm)
New born: 30 weeks 2.5 ± 0.4 1.5
New born: 34 weeks 3.0 ± 0.4 2.0
New born: term 3.5 ± 0.4 2.5
0–5 months 3.9 ± 0.8 1.9
6–12 months 4.3 ± 0.8 2.3
1–2 years 4.7 ± 0.8 2.6
2–3 years 5.1 ± 0.9 2.9
3–4 years 5.5 ± 0.9 3.3
4–5 years 5.7 ± 0.9 3.5
5–6 years 6.0 ± 0.9 3.8
6–7 years 6.1 ± 0.9 3.9
7–8 years 6.2 ± 1.0 3.7
8–9 years 6.3 ± 1.0 3.8
9–10 years 6.3 ± 1.0 3.8
10–11 years 6.4 ± 1.1 3.7
Adult 13.3 ± 1.6 9.3
Adapted from Indian Journal of Pediatrics 2000; 67:455–460
- What are the causes of micropenis?
Micropenis is defined as a stretched penile length <−2.5SD for that particular
age. The causes of micropenis include hypogonadotropic hypogonadism,
hypergonadotropic hypogonadism, disorders of androgen biosynthesis and
action, and isolated growth hormone deficiency (Fig. 7.8).7 Delayed Puberty