Do boys typically begin to produce semen after their peak growth rate?

Last updated on April 5, 2024

Question:

Hello Minister,

I am a 16-year-old male who is at stage 3.7, according to your calculator. I am quite late to puberty, having only noticed terminal pubic hair last year. However, according to many people I know, I have had a growth spurt in the past year. At early 15, I was 168 cm (5’6), and currently, I am 175 cm (5’9). Around the same time I had my growth spurt, I began to ejaculate semen. I saw on a medical website that boys typically begin to produce semen after their peak growth rate. Is this true?

However, I am mainly concerned about my voice. I would desperately like my voice to change as I often get made fun of for my childlike voice, which has not changed. I also have a very childlike figure with a baby face. I asked my father when his voice changed, and he said that he could not remember, but it was “around 17.” Will I follow the same pattern as him? Are there any patterns in growth that will determine when my voice will change?

Thank you!

Answer:

Noticeable pubic hair usually appears midway through stage 2. You then started your growth spurt about six months later, so I think the calculator gave you a slightly higher estimate than I would expect. Ejaculations can start anywhere from the middle of stage 2 to the middle of stage 4. Therefore, only about half of all boys start after their peak growth rate.

The voice changes during stage 4. You might notice a slight lowering in stage 3, but the most noticeable change will be in stage 4. Since you are roughly mid-stage 3, you will probably have to wait a year or so for your voice to change. While boys roughly follow the pattern of their fathers, each person has a different mixture of genes, so many things will be different.

Question:

Thank you for responding to my question!

I would just like to add that recently, my penis length has shot up. It went from 13 to 15 cm in the span of about a month or two. I also notice sparse, thin hairs about half a cm under my arms. Does this mean that my testosterone is increasing? How much testosterone do I need to develop male secondary sex characteristics like a deep voice, body hair, facial hair, etc? Or does it only matter if the body is exposed to testosterone for a certain amount of time? I don’t really understand.

Thank you!

Answer:

Your testosterone level is quite low during childhood, but it dramatically changes when you reach puberty. Puberty is defined as the point in time when your testosterone level shoots up. This happens about a year before you see any external signs of changes. The graph makes the changes look smooth, but the initial years of changing hormone levels bounce around as the body learns to regulate its testosterone production. After your growth finishes, your hormone level settles down and remains basically the same for the rest of your life.

You don’t have any control over this process. It is merely how your body was designed and how it operates.

The changes that take you from a boy’s body to a man’s body occur over an eight-year period. You are about halfway through the changes. See Development Stages for details.