JACKINWORLD PUBERTY SURVEY
This Survey was held in July 1998 over a period of about five days. It was open to males age 19 and under. A total of 2,476 responses were collected. For most questions a small number of participants (fewer than 1%) gave no answer; therefore for any given question, the results below consider only those who answered the question.
1. What is your current age?
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11 or younger | 0.2% | |
12 | 1.7% | |
13 | 6.4% | |
14 | 13.1% | |
15 | 21.0% | |
16 | 20.0% | |
17 | 16.4% | |
18 | 10.9% | |
19 | 10.4% |
Overall average age: 15.9
2. What is your ethnicity based on the origin of your ancestors?
|
African (black) | 2.0% | |
Asian/Pacific Islander | 6.6% | |
European (white) | 83.6% | |
Latin-American/Hispanic | 3.7% | |
Middle Eastern/Semitic | 0.8% | |
Native American | 1.1% | |
Other | 2.1% |
3. When you started going through puberty, which of the following developments happened first?
|
Rapid growth of penis | 10.9% | |
Rapid growth of testicles/scrotum | 6.5% | |
Appearance of pubic hair | 69.6% | |
I haven't started puberty yet | 0.6% | |
I can't remember | 12.3% |
|
Appearance of pubic hair is by far the most commonly reported first sign of puberty. However, since pubic hair is much more noticeable than, say, an increase in penis size (unless the person has been measuring his penis frequently as puberty approaches), these results are not necessarily conclusive. |
4. How old were you when you saw the first signs of puberty (from the previous question)?
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10 or younger | 12.0% | |
11 | 31.6% | |
12 | 36.0% | |
13 | 15.5% | |
14 or older | 4.5% | |
I haven't started puberty yet | 0.5% |
Puberty Onset Age, by Ethnicity:
African (black): 11.3
Asian/Pacific Islander: 12.1
European (white): 11.7
Latin-American/Hispanic: 11.6
(Sample for other groups too small to be statistically significant)
5. Which of the following did you experience first?
|
Orgasm by masturbating, but I didn't ejaculate | 45.7% | |
Ejaculation by masturbating | 37.1% | |
Nocturnal emission ("wet dream") | 13.6% | |
Spontaneous ejaculation (e.g., while making out with a girl) | 2.3% | |
Orgasm through sexual intercourse | 0.6% | |
I have neither orgasmed nor ejaculated yet | 0.6% |
6. How old were you when you experienced your first ejaculation (either through masturbation or nocturnal emission)?
|
11 or younger | 16.8% | |
12 | 34.8% | |
13 | 32.2% | |
14 | 11.5% | |
15 or older | 3.4% | |
I have never ejaculated | 1.3% |
Average Age of First Ejaculation & Puberty Onset:
For those who started puberty at age 11 or earlier: 11.9
For those who started puberty at age 12: 12.6
For those who started puberty at age 13 or later: 13.5
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On the average, a male's first ejaculation occurs within a year after puberty begins. |
7. On the average, about how often do you have a nocturnal emission ("wet dream")?
|
Twice or more a week | 2.0% | |
Once a week | 3.3% | |
Once every two weeks | 4.9% | |
Once a month or less but I do get them occasionally | 40.5% | |
I've never had a nocturnal emission | 49.2% |
|
Not surprisingly, nocturnal emissions are fairly rare among JackinWorld readers. They are more common in males who masturbate less often (see question #8). |
8. On the average, about how many times per week do you masturbate to orgasm?
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21 or more times per week (at least 3x per day) | 6.8% | |
14-20 times per week | 17.5% | |
10-13 times per week | 16.1% | |
7-9 times per week | 25.5% | |
4-6 times per week | 22.2% | |
2-3 times per week | 9.9% | |
once or less per week | 2.0% |
Average Masturbation Frequencies by Age:
11: 11.1 times per week
12: 9.4
13: 10.6
14: 10.6
15: 9.9
16: 9.6
17: 9.4
18: 8.5
19: 9.3
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Average masturbation frequency decreases only slightly as a male passes through his teen years. |
Masturbation & Nocturnal Emissions:
Of those age 14 or older who masturbate at least 7-9 times per week, the average nocturnal-emission frequency is less than once per month. Of those age 14 or older who masturbate once or less per week, the average nocturnal-emission frequency is about once every three weeks.
9. With regard to your masturbation frequency over time, which of the following is most true?
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I masturbate much more often than I did when I first started | 34.3% | |
I masturbate slightly more often than I did when I first started | 23.6% | |
I masturbate about the same amount as when I first started | 17.9% | |
I masturbate slightly less often than I did when I first started | 18.7% | |
I masturbate much less often than I did when I first started | 5.5% |
|
This seems to contradict the findings from question #8 although for this question, the time span for "when I first started" was not defined. Someone might have masturbated twice in the week he discovered masturbation and a month later might be masturbating ten times a week, only to throttle back to seven times a week several years later; this person could answer this question a number of different ways. |
10. Which of the following best expresses your feelings about your masturbation frequency?
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I masturbate way too often and wish I could cut down | 10.6% | |
I probably masturbate too much, but I have no interest in cutting down | 22.7% | |
I'm fine with the amount of masturbation I do | 61.0% | |
I should masturbate more often | 5.7% |
11. On the average, about how many times per month do you masturbate to orgasm in full view of another person who is also masturbating?
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I have never done it, but wouldn't mind trying | 50.6% | |
I have never done it and don't want to | 9.7% | |
8 or more (at least twice a week) | 2.9% | |
4-7 per month | 2.6% | |
2-3 per month | 4.9% | |
1 or less per month, but I've done it more than once in my life | 18.9% | |
I've done it only once | 10.4% |
12. When you've masturbated with another person, how often was it a male and how often was it a female?
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I've never done it | 58.8% | |
I've masturbated with males only | 29.5% | |
I've masturbated with both sexes, but with males more often | 4.8% | |
I've masturbated with both sexes equally, or with females more often | 2.7% | |
I've masturbated with females only | 4.2% |
13. Which of the following best describes the amount of facial hair you have?
|
I pretty much don't have any facial hair yet just "peach fuzz" | 14.9% | ave. age: 14.6 | |
I have a few whiskers near my ears or on my chin or upper lip | 30.1% | ave. age: 15.5 |
I have a good amount of hair on my upper lip and cheeks, but not yet under my chin/on my upper neck | 21.6% | ave. age: 16.0 | |
I could grow a pretty full beard if I didn't shave | 33.4% | ave. age: 17.0 |
14. Amount of Pubic Hair Over 1/2" Long
Participants were asked to look at an actual-size illustration of pubic-hair outlines and pick the one that most closely matches their own. (They were cautioned to set their monitor's resolution correctly; on Windows machines this may correspond to a resolution of 800 x 600, and on Macintoshes, 1024 x 768. If in doubt, use the 1" reference marker on the illustration below.) Based on the responses, we've averaged the outline sizes for each age, as seen here:

Percentages who reported having any pubic hair at all over 1/2", by age:
|
11 | 33.3% | |
12 | 88.1% | |
13 | 98.1% | |
14 | 99.4% | |
15 | 99.4% | |
16 | 99.8% | |
17 | 99.8% | |
18 | 100% | |
19 | 100% |
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Most males first get pubic hair between their 12th and 13th birthdays. It usually grows in area at a fairly steady rate until about age 14. |
15. Amount of Underarm Hair Over 1/4" Long
Participants were asked to look at an actual-size illustration of underarm-hair outlines and pick the one that most closely matches their own. Based on the responses, we've averaged the outline sizes for each age, as seen here:

Percentages who reported having any underarm hair at all over 1/4", by age:
|
11 | 16.7% | |
12 | 60.1% | |
13 | 77.2% | |
14 | 89.5% | |
15 | 97.1% | |
16 | 98.2% | |
17 | 99.0% | |
18 | 99.6% | |
19 | 99.6% |
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Most males first get axillary (underarm) hair before their 13th birthday, although many do not get it until they are 14 or 15. |
16. Do you have hair longer than 1/4" growing on your scrotum?
Percentages of "yes" responses, by age:
|
11 | 16.7% | |
12 | 40.5% | |
13 | 69.9% | |
14 | 78.6% | |
15 | 81.5% | |
16 | 83.5% | |
17 | 82.6% | |
18 | 87.7% | |
19 | 88.0% |
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On the average, scrotal hair appears about a year after axillary (underarm) hair although about a tenth of males never grow scrotal hair. |
17. Do you have hair longer than 1/4" growing on your crotch or near your anus?
Percentages of "yes" responses, by age:
|
11 | 0.0% | |
12 | 34.1% | |
13 | 53.8% | |
14 | 74.5% | |
15 | 76.7% | |
16 | 80.9% | |
17 | 78.5% | |
18 | 83.5% | |
19 | 82.0% |
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On the average, perineum (crotch) hair appears slightly later than scrotal hair although about a fifth of males never grow perineum hair. |
18. Has your voice changed yet?
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Yes it started changing at least a year ago | 69.0% | |
Yes it started changing within the past year | 15.9% | |
No it's still pretty high | 4.0% |
It's not really that high, and I'm pretty much done with puberty, but I never really noticed it changing | 11.1% |
Average age of those who said voice started changing within the past year: 14.7
|
Voice-changing occurs relatively late in puberty, on the average quite a bit later than first ejaculation or appearance of pubic or underarm hair. |
19. What kind of underwear do you wear more often?
|
Boxers | 49.7% | ave. age: 15.9 | |
Briefs | 47.4% | ave. age: 16.0 | |
I rarely or never wear underwear | 2.9% | ave. age: 15.8 |
Underwear Type & Average Masturbation Frequency:
Boxers-wearers: 9.6
Briefs-wearers: 9.5
Underwear-free: 12.8
|
The number of boxers-wearers and briefs-wearers is remarkably similar. Type of underwear does not seem to affect masturbation frequency, although going without underwear may make a person masturbate more. Or, those who masturbate more often may for whatever reason dislike wearing underwear. These results are not entirely conclusive, though, because our sample number of underwear-free participants was fairly small (72 total). |
20. When you're nearing the climax of a masturbation session, how often do you think about other guys?
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Never or almost never | 35.7% | |
Sometimes | 31.7% | |
Usually | 14.7% | |
Almost always or always | 18.0% |
21. Which of the following do you wish you had more of?
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Pubic hair | 3.1% | ave. age: 14.8 | |
Underarm hair | 4.9% | ave. age: 15.1 | |
Facial hair | 4.4% | ave. age: 15.9 | |
Height | 12.9% | ave. age: 16.1 | |
Body muscles | 59.5% | ave. age: 16.0 | |
I feel fine about all of the above | 15.2% | ave. age: 16.1 |
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Younger males are more interested in getting more body hair, but as they get older (and grow more body hair) they become more interested in growing taller and gaining muscles. |
22. Penis Size
Participants were asked to measure their erect penis using a precise, uniform method and were told, "If you have even the slightest temptation to lie or exaggerate your measurement on this survey, or if you aren't interested in getting a precise measurement by using the method outlined below, please do us all a favor and skip the next question." This was the measurement method:
With a rigid ruler handy, standing straight up or kneeling, get a full erection. Lay the ruler along the top of your penis, and press the end of the ruler firmly against your body (where the pubic hair is). Hold your penis against the ruler with your hand, straighten out as much as possible any curvature that may exist, and try to hold your penis so that it's sticking straight out from your body. Then determine the ruler reading at the very end of your penis and round off to the nearest quarter-inch. If your ruler has centimeters only, calculate the number of corresponding inches (1 inch = 2.54 cm) and write it down.
Average erect penis length, by age:
|
11 | 3.29" | |
12 | 4.10" | |
13 | 5.34" | |
14 | 5.74" | |
15 | 6.04" | |
16 | 6.18" | |
17 | 6.27" | |
18 | 6.29" | |
19 | 6.25" |
Overall average penis length for all ages: 6.03
1.4% of participants clicked a button that said, "I am unable to answer this question without lying or exaggerating."
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On the average, the penis grows most dramatically between a male's 12th and 13th birthdays. Size-averages from this Survey are similar to those from the JackinWorld Survey #3, although (curiously) a bit higher this time. The measurement specifications were exactly the same for both Surveys. |
Penis Size & Puberty Onset: (taken from participants ages 17-19)
Of all participants ages 17-19:
For those who started puberty at age 11 or earlier, average penis size is 6.44".
For those who started puberty at age 12, average penis size is 6.26".
For those who started puberty at age 13 or later, average penis size is 6.08".
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From these results it seems that the earlier somebody begins puberty, the larger his penis ends up being. This could be hormone-related, or simply because the penis has more time to grow during the time the sex characteristics are developing. Or, these results could have been skewed because people inclined to exaggerate how early puberty began for them may also be inclined to exaggerate their penis size. |
Penis Size & Underwear Type: (taken from participants ages 15-19)
Of all participants ages 15-19:
For those who wear boxers-style underwear, average penis size is 6.24".
For those who wear briefs-style underwear, average penis size is 6.11".
For those who prefer not to wear underwear, average penis size is 6.29".
|
This result was surprising. It would appear there is some minor correlation between a male's penis size and the type of underwear he wears. One popular belief is that if you let the penis "hang out" more (by wearing less restrictive clothing), the penis will tend to stretch and grow, but that makes little scientific sense. It seems more likely that males with larger penises are more likely to wear less-restrictive clothing because they like the way their penis feels loose under their clothes, while for less pendulous males this is less of a concern. |
23. How do you feel about the length of your erect penis?
|
I think it's smaller than normal for my age | 26.7% | ave. age: 15.9 | ave. size: 5.35" | |
I think it's about average size for my age | 59.5% | ave. age: 16.1 | ave. size: 6.13" | |
I think it's larger than normal for my age | 13.8% | ave. age: 15.5 | ave. size: 6.97" |
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Teen males are twice as likely to believe their penis is below average size than they are to believe it's larger than average. Of course, in reality, the number that are below average and the number that are above average are more or less equal. |
24. Testicle Size
Participants were asked to look at an actual-size illustration of testicle outlines and pick the one that most closely matches their own. They were told that if one testicle is larger than the other to go with the larger one. They were also told, "Skip this question if you're unable to determine your testicle size please don't guess." Based on the responses, we've averaged the outline sizes for each age, as seen here:

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On the average, the testicles grow most dramatically between a male's 12th and 13th birthdays. Rapid testicle growth usually occurs slightly later than rapid penis growth. |
25. Which of the following of your body features are you most proud of?
|
My height | 30.9% | ave. age: 16.0 | |
My muscles/build | 13.8% | ave. age: 16.1 | |
My body hair | 8.5% | ave. age: 15.9 | |
My genitals | 31.9% | ave. age: 15.8 |
None of the above -- I don't like my body | 14.9% | ave. age: 16.0 |
Of those who are most proud of their genitals, average masturbation frequency is 10.4. (Overall average: 9.7)
|
A teen male's choice of "best body feature" doesn't change significantly over time. Those who are proud of their genitals masturbate slightly more often than others. |
26. These days, how often do you get unwanted spontaneous erections?
All the time -- at least once an hour | 9.5% | ave. age: 15.2 |
Pretty often (maybe a few times a day) | 49.0% | ave. age: 15.8 |
Every once in a while (maybe once every couple of days | 33.3% | ave. age: 16.3 | |
Rarely or never | 8.2% | ave. age: 16.3 |
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Spontaneous erections are most common in the early teen years; they gradually decrease in frequency. |
Spontaneous Erections & Underwear Type:
For those who wear boxers-style underwear, percentage of readers saying they get spontaneous erections "all the time" or "pretty often": 60.4%.
For those who wear briefs-style underwear, percentage of readers saying they get spontaneous erections "all the time" or "pretty often": 55.9%.
For those who prefer not to wear underwear, percentage of readers saying they get spontaneous erections "all the time" or "pretty often": 63.4%.
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Since we found virtually no correlation between underwear preferences and age, these findings would suggest less-restrictive clothing is more likely to result in spontaneous erections. |
27. Which of the following best describes how much you think about sex (masturbation, intercourse, sexually attractive people, etc.) throughout the day?
|
I think about it all the time! | 18.3% | ave. age: 15.7 |
I think about it pretty often (like every five or ten minutes) | 31.6% | ave. age: 15.9 |
I think about it every once in a while (like once an hour or two) | 47.6% | ave. age: 16.1 | |
I rarely think about it | 2.5% | ave. age: 16.1 |
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Sexual thoughts are most common in the early teen years; like spontaneous erections, they gradually decrease in frequency but not quite as much. Of course, men have frequent sexual thoughts throughout their lives, even though the occurrance of spontaneous erections is rare in many adult males. |
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