Stretched penile length age-specific reference values
Published age-specific reference values for stretched penile length (SPL) are population- and measurement-protocol dependent. [1]
Age-specific percentiles for SPL (cm)
The following SPL reference percentiles (5th, 50th, 95th) are reported for healthy boys by age group (measured with a ruler from the pubic ramus to the tip during stretching). [1]
| Age | 5th percentile (cm) | 50th percentile (cm) | 95th percentile (cm) |
|---|---|---|---|
| 0 to 11 months | 2.29 | 3.01 | 3.09 |
| 1 year to 1 year 11 months | 3.89 | 3.98 | 4.11 |
| 2 years to 2 years 11 months | 4.02 | 4.16 | 4.30 |
| 3 years to 3 years 11 months | 4.10 | 4.32 | 4.47 |
| 4 years to 4 years 11 months | 4.16 | 4.35 | 4.54 |
| 5 years to 5 years 11 months | 4.27 | 4.51 | 4.65 |
| 6 years to 6 years 11 months | 4.27 | 4.56 | 4.82 |
| 7 years to 7 years 11 months | 4.46 | 4.73 | 4.90 |
| 8 years to 8 years 11 months | 4.61 | 4.92 | 5.09 |
| 9 years to 9 years 11 months | 4.68 | 4.86 | 5.20 |
| 10 years to 10 years 11 months | 4.80 | 5.16 | 5.37 |
| 11 years to 11 years 11 months | 5.04 | 5.52 | 5.83 |
| 12 years to 12 years 11 months | 5.80 | 6.33 | 6.77 |
Micropenis-related age cutoffs used in clinical definitions
A commonly used international consensus defines micropenis as SPL less than 2 cm at birth and SPL less than 4 cm after age 5 years. [2]
Measurement protocol used in the cited age-specific reference values
SPL is measured from the pubic ramus to the tip after stretching, using a transparent ruler and pressing the suprapubic pad of fat. [1]