The doctor measured my testicles to be 20-25 ml but everything else about me indicates I’m in stage 3. How can this be?

Last updated on September 6, 2023

Question:

Hello,

I have a question. I went to get my bone age checked so they could predict my height. I’m almost 165 cm. My age is 16 years and 7 months old but the bone age test showed 13 years and 9 months old. I’m confused about one thing. My voice has only dropped this year. I had a squeaky voice and babyface a year ago. I have grown almost 4 inches since. They also checked my testicles which came out to be 20-25 ml which means a mature stage 5. But the prediction they gave me was that I would end up between 174-178 cm and the Tanner stage calculator gave me an estimate of 3.7. My armpit hair recently started growing; however, it’s little and I have zero facial hair. Pubic hair looks like in stage 3 but my testicle size says 20-25 ml which is stage 5. How is this possible? Does this mean my penis is already done growing? How can this be the case if my voice and face only changed last year and I look like I’m in stage 3 based on pubic hair, recently growing armpit hair, and no facial hair? 

Answer:

The ages given as the result of the bone age test are meant to represent the average boy, though the values are a bit skewed. Basically, your bone age test shows that you are developing slower than average. A bone age of 13.7 puts you in the middle of Tanner Stage 3. The calculator also estimated that you are in the middle of stage 3. The only item off is your testicle size. Either you have larger-than-average testicles or the measurement was wrong.

Question:

Hello,

I know it seems weird, but it was done at a big hospital by a pediatric doctor so he knows what he’s doing. He measured it with an orchidometer. All the information was in the letter he sent after the bone age test. It says the genitalia is manly and that it’s 20-25 ml, which seems weird since it doesn’t match up with my bone age and physical signs I seem to be in tanner 3. Also, does this mean that my genitalia, like my testicles, developed faster? I’ve definitely seen an increase in penis size this year while my height increased by almost 4 inches.

Answer:

I’ll accept that your testicle size is unusually large for the stage of development that you are in. Since it is the only thing that is unexpected, then we look for another simple answer. It may just be that you have larger than average testicle size, just as some guys have bigger feet than other guys. The average adult male’s testicles are 18 ml, but the range that is considered normal is 15 to 20 ml and the entire range is between 12 and 30 ml. It sounds like you might be among the unusually large size by the time you finish growing.

Since everything else indicates you are in stage 3, then that is where you are in your development. You are still in your rapid growth phase, which is also the phase the penis grows the most in length.