Boys reach sexual maturity younger and younger

Boys reach sexual maturity younger and younger
Fatal Recklessness: with production of male hormones in puberty at its highest level, the probability for a boy in the U.S.A. to die in the year 2007 rose from 2 out of 10,000 at age 13 to more then the sevenfold at age 21 (i.e. 15 out of 10,000). Credit: MPIDR, Human Mortality Database

(Medical Xpress) -- Boys are maturing physically earlier than ever before. The age of sexual maturity has been decreasing by about 2.5 months each decade at least since the middle of the 18th century. Joshua Goldstein, director of the Max Planck Institute for Demographic Research in Rostock (MPIDR), has used mortality data to prove this trend, which until now was difficult to decipher. What had already been established for girls now seems to also be true for boys: the time period during which young people are sexually mature but socially not yet considered adults is expanding.

"The reason for earlier maturity for boys, as with girls, is probably because nutrition and disease environments are getting more favourable for it," says demographer Joshua Goldstein. It has long been documented by that girls are experiencing their first menstruation earlier and earlier. But comparable data analysis for boys did not exist. Goldstein resolved this gap by studying related to mortality. When production during reaches a maximum level the probability of dying jumps up. This phenomenon, called the "accident hump", exists in almost all societies and is statistically well documented.

Goldstein discovered that the maximum mortality value of the accident hump shifted to earlier age by 2.5 months for each decade since the mid-1700s, or just over two years per century. Accordingly, the age of boys’ sexual maturity decreased at the same rate. Essentially, the data showed that the age of is getting younger and younger since the accident hump is occurring earlier and earlier. (Research included data for Sweden, Denmark, Norway, Great Britain and Italy. Since 1950 the data is no longer clear but indicates stagnation.) The maximum of the accident hump occurs in the late phase of puberty, after males reach reproductive capability and their voice changes.

When boys get physically mature they take more risks and the risk of death increases

The accident hump, which also exists among male apes, occurs because young men participate in particularly risky behaviour when the release of the hormone testosterone reaches its maximum. Dangerous and reckless shows of strength, negligence, and a high propensity to violence lead to an increased number of fatal accidents. The probability remains low, but the rate jumps up considerably (see graphic).

In respect to the developmental stage of the body "being 18 today is like being 22 in 1800" says Joshua Goldstein. He sees the main causes as better nutrition and an improved resilience against diseases. Because the decline began long before the intervention of the automobile (accompanied by a high risk of accident) it appears that the shift in age of maturity is biological, and not related to technological advancements or social activities. When the use of automobiles or guns became common no significant effect on the data could be seen.

Albeit giving evidence for the age shift only indirectly via , Joshua Goldstein underlines the importance of its biological meaning:  "Researchers see for the first time how females and males have been equally responsive to changes in the environment."

The onset of biological versus social adulthood is drifting apart

"The biological and social phases in the lives of young people are drifting apart ever stronger", says Josh Goldstein. "While adolescents become adults earlier in a biological sense, they reach adulthood later regarding their social and economic roles." Life cycle research shows that for more than half a century the age at which people marry, have children, start their careers and become financially independent from their parents continues to rise.

According to Joshua Goldstein, this doesn’t only extend the period of physical adulthood during which do not yet have children. "Important decisions in life are being made with an increasing distance from the recklessness of youth." The demographer points out that it remains unclear whether the "high-risk phase" of adolescence becomes more dangerous for males because it starts earlier. While younger men are less mentally and socially mature, parents also tend to supervise their children more closely when they are younger.

More information: Joshua R. Goldstein, A Secular Trend toward Earlier Male Sexual Maturity: Evidence from Shifting Ages of Male Young Adult Mortality, Plos one, 16 August 2011
Citation: Boys reach sexual maturity younger and younger (2011, August 18) retrieved 19 October 2019 from
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Aug 18, 2011
I think it probably has something to do with the mind.

Sex is as much a mental thing as a physical thing.

If the mind knows more information, such as in improving education over the centuries, then people reach certain mental maturity benchmarks earlier, even if they haven't reached what we consider independence or social maturity.

Young people are often more educated than their parents, and are born into a world which is a full generation more advanced than the previous.

Now it's computers and cell phones. In the past it was the musket and rifles, then a better sail boat, and then steam engines, and so on.

Technology and knowledge puts mental pressure on the brain, a pressure to learn and mature at a faster and faster pace with each generation.

Since the mind and sex hormones have feedback relationships, increasing the general purpose activity and pressures on the young mind through increase volumes of education may be activating sex hormones earlier and earlier.

Aug 18, 2011
Consider this, almost all technology that was ever invented was invented in the past few hundred years, particularly during the age of exploration and the colonial period, into the industrail revolution, which is exactly coincidental with most of this data.

There is increased pressure to do more and learn more with each generation, and as I speculated, the mind is in a feedback relationship with other systems. Change the mind, even in seemingly "irrelevant" ways, and it clearly impacts other body functions.

Today kids graduate high school with up to 5 math courses beyond algebra 1, which they now take in 7th or 8th grade in some cases. Two generations ago, what we consider Algebra 1 and maybe some home economics or "business math" was about all they did in high school.

Additionally, males and females interact in LARGE social groups more and more often in recent centuries. In ancient time, you might live on a farm in the middle of nowhere. Now, everyone lives in high population

Aug 18, 2011
And even though people are educated to an almost obscene degree now, in most cases, it doesn't help young people establish themselves financially any sooner, because it has gotten to where, in some cases, it literally takes a life time worth of education and experience just to get an entry level job, unless you're talking about bottom tier "unskilled" labor jobs, which can't sustain a family.

Additionally, in the past people had 100 acres of land, and left it to their children, which gave them FREE land, and often a free house.

In the past few generations, people own a house, usually on less than an acre of land, and parents live to their 90's and there is no inheritance, which makes it much more difficult for newer generations to have anything. In reality, the newer generations work harder than the older, in spite of their elders' BS complaints, because they often start with NOTHING of their own.

Aug 18, 2011
While no one of these issues could explain this alone, I think the mental feedback is most important to hormonal response. Clearly, the data suggests this has been going on since the time of the industrial revolution, if not a bit sooner.

Recall, that even in the early industrial revolution, even up to a few decades ago, kids worked in sweatshops, forced to learn ever increasing technologies at a younger and younger age compared to their parents or grandparents.

In most cases, a high school sophomore is more educated than a college graduate from 30 or 40 years ago, and is at least 2 or 3 times as educated as a high school senior from 30 or 40 years ago, especially in math and science, and nobody even really gives any thought to that. They get "bad" math scores maybe, but my God, they're taking a foreign language, and then advanced trigonometry and calculus in like 11th grade now vs my elders, who in some cases never even took Algebra 2 or geometry.

Aug 18, 2011
And of course, one of the most obvious examples of how a simple mental pressure can create a hormonal response is Adrenaline.

Scare the hell out of someone, and they get an adrenaline rush, which then further enhances the fight or flight response.

"Irrelevant" mental pressures probably work the same way on sexuality and sex hormones.

Aug 18, 2011
Holy spambots, batman!

Techno1/QC last comment: 8/17/11 - 11:27AM, after a blistering pace of 1 post ever 10 minutes or so he goes silent.

Nanobanano account created: 8/17/11 - 13:27PM, and he has set a blistering pace of ~1 post ever 10 minutes or so.

What a coincidence.

On topic: Without having read the article I was thinking it was related to nutrition. Just as the phenomenon in girls has been linked. And this:
"The biological and social phases in the lives of young people are drifting apart ever stronger", says Josh Goldstein.

... as well as the author's own reckoning, would seem to back that up I believe more so than say, technology / societal; or "mental feedback" as QC/Techno/Nanobanano would inaccurately classify those.

Aug 19, 2011
Via changes to the diurnal cycle from increased use of artificial lighting, more daylight = accelerated maturation.

Aug 24, 2011
That's awesome news. And with most partents still not talking to their children about sex we can look forward to even younger kids having children and raising more kids. The children's world revolution is upon us!

Aug 25, 2011
Could it be that this is nothing at all to do with hormones and recklessness but more to do with pressure from society to grow up.

I'd say no, because it's a well observed trends that "kids" (which is to say young adults) are living with their parents longer then ever before. If anything there is less pressure than ever before to grow up sooner. It's well documented that the recent generation is if anything over-coddled.

Kids (which is to say young adults) may be exposed to more "adult material" due to the prevalence of media today, which may be perceived as pressure to grow up, but it in fact is not even close to the same as "pressure to grow up".

In the early 1900s, kids had pressure to grow up, they were getting married and having real, hard labor jobs by the time they were 18-20. "Juvenility" is being prolonged as time goes by, for many reasons (such as people live longer and jobs "require" more education), not shortened. Get real.

Aug 25, 2011
Hey em

I looked up 'juvenility', because its the type of word I would never be caught dead using and I figured it was made up anyways, but I found this:

"MANN TALK: The Juvenility of Gun Lovers and NRA Members...
Perry Mann is a former teacher, a lawyer, a former prosecuting attorney of Summers County and a columnist for Huntington News Network. He lives in Hinton, WV. He turned 90 this year; he was born in Charleston, WV in 1921."

-Is this you? Is juvenility the opposite of senility perhaps? Or more like a reciprocal?

Sorry Im being sophomoric I guess. This is the best I can do by mid-afternoon as the voices become intrusive

Aug 25, 2011
Sorry, not me.

I put that in quotes because I knew it was a made up word... and actually I did intend it to be a kind of mix between juvenile and senility. Because young adults these days, who by all reckoning should be functioning adults, are behaving in some sort of reverse senility fashion, still unable to care for themselves well after they should be doing so.

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