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Sun 6 May, 2007 04:17 pm
I caught the end of a program that said 100yrs ago girls hadd their first period at around 16 or 17. Today we have girls who get their first period as early as nine! Boys and girls are obviously maturing physically earlier than they were, and even intellectually too? We know people are generally smarter than they have been any time in the past, but are children more emotionally and intellectually mature than before? And just why are they maturing physically at younger and younger ages?
Nutrition or Added Hormones to dairy, Poultry and Beef?
the theories I have head are that is better nutrition.
FWIW, personally, I think hormones (like BVG ...Bovine Growth formula) added to dairy cows, hormones added to raising of poultry and meat could be contributing, too. Who had ever heard of 9-yr-old girls having their period ...say prior to the '60s and '70s?!
Quote:I caught the end of a program that said 100yrs ago girls hadd their first period at around 16 or 17.
I'm not sure I believe that.
100 years ago people didn't live as long. Girls typically married young and, if I recall correctly, usually were having children by 16 or 17.
I can go along with ragman's idea of a gradual decline in age starting about the 60s or 70s but 100 years ago.....? I think there was a gradual increase in age leading up to the decline.
I'll have to dig up some long burried reading to confirm so let's just say this is my long winded bookmark.
Re: Why Are Children Maturing Earlier?
Quincy wrote:I caught the end of a program that said 100yrs ago girls had their first period at around 16 or 17. Today we have girls who get their first period as early as nine! Boys and girls are obviously maturing physically earlier than they were, and even intellectually too?
"Today we have girls who get their first period as early as 9."
The above statement does not tell us anything about the
mean. We have more people on this planet now, and better communication of information...when you have more data samples, and lose less of them, you should expect the recorded minimum and maximum to have higher variance given an identical distribution.
Now, in all likelihood, I would expect that some areas of mental maturation come earlier because a big aspect of maturity is knowledge, and the information content and accessibility over the past 100 years has been growing exponentially.
I would be interested to know upon what basis any kind of claim is made about the onset of menstruation in 1907. I frankly consider it suspect, if for no other reason than that there is likely not a reliable basis to make the claim.
Betrothals and marriages of quite young people have been a commonplace throughout history--and accounts for many of the "odd" ages of consent, for example, in states of the United States. In North Carolina, for example, as recently at least as the 1960s, the age of consent for women was 14 years of age. While working in a hospital in south-side Virginia in 1972, on Christmas Eve i encountered a woman, 31 years of age, who was there to deliver a child. Her gravidity was 15 and her parity was 13. That meant that she had been pregnant 15 times, and had delivered 13 live births. To aid arranged marriages, the age of consent in Delaware was, for quite a long time, seven years of age (this is not imply that seven year old girls were delivering children, but rather that they would be betrothed at that age).
Matilda (or Maude) of Anjou (also known as "The Empress Matilda") was betrothed to the Holy Roman Emperor, Henry V, at age seven, and married when she was thirteen (1114). She and Henry had a single child, who did not, however, survive infancy. Eleanor of Aquitaine married Louis VII when she was 15 years of age (1137). Isabella of France was betrothed to Edward, Prince of Wales (to become King Edward II of England), at age three, but Edward's father, King Edward I, changed his mind, so she was not brought to England until Edward I died in 1307, when she was twelve. She and Edward II married in 1308, when she was not yet thirteen years of age. Although her husband was a homosexual, and in fact gave her no wedding gifts, while piling gold and gifts on his lover, Piers Gaveston, they nevertheless produced four children, the first being Edward of Windsor, who was to become King Edward III, who began the Hundred Years War with France (basing a claim to the French throne on his mother). Edward of Windsor was born in 1312, when Isabelle was not yet 17 years of age, and she conceived, therefore either just before or just after her 16th birthday (her birthday is not certain, but sometime in 1295, probably late in the year).
If i were to search around on the web, i could probably find many more examples.
Quote:Lina Medina (born September 27, 1933 in Paurange[citation needed], Peru) gave birth at the age of 5 years, 7 months and 21 days and is the youngest confirmed mother in medical history.
<snip>
Although the case was called a hoax by some, a number of doctors over the years have verified it based on biopsies, X rays of the fetal skeleton in utero, and photographs taken by the doctors caring for her. Extreme degrees of precocious puberty in children under 5 are very uncommon but not unheard of. Pregnancy and delivery by a child this young remains extremely rare because extremely precocious puberty is treated to suppress fertility, preserve growth potential, and reduce the social consequences of full sexual development in childhood, and because termination of such pregnancy is more widely available now than in the early 20th century.
It is said that she started menstuating at 8 months.
A quick search of precocious puberty and menarche turned up some interesting information like....
Quote:Some of the aspects of family structure and function reported to be independently associated with earlier menarche:
The increased incidence of childhood obesity (reaching a body weight of 100 lbs or 45kg appears to be an important "trigger" for the very young reaching menarche--both estrogen and progesterone are fat-soluble hormones).
Absence of father from the home from early childhood
High conflict family relationships
Living in an urban environment
Some of the aspects of family structure and function reported to be independently associated with later menarche:
Larger family size
Warmer, closer or more positive relationship with biological father
Warmer, more supportive, low stress family environment
Having a number of older sisters
... but I haven't found anything remotely like a real historical comparison.
I think it has to do with better nutrition.
People are taller and live longer than they used to - doesn't seem too big a stretch to me that they would reach sexual maturity a bit faster, as well.
Yes, but those examples Settin' Aah -aah gave would not be sufficient to deal with stuh's point about the "mean".
After all there must be a lot of guys who can run 100 meters in less than 10 seconds and you could list them until you are blue in the face in order to show off your knowledge of athletics records but I'd bet that if you took the "mean" into account we could well be the slowest human beings history has ever witnessed. At running I mean.
You are obsessed with the "Big -Time" Settin' Aah-aah.
I totally agree with what boomer, Stuh, and Setanta have noted about the premise being suspect.
I've read a lot about what boomer mentions, though, that the average age of menarche is getting lower/ younger within some unspecified time period (50 years?) and that obesity is widely thought to have something to do with it. Fat and estrogen interact in certain ways. (I forget how that works, can look it up.)
The stress one rings a bell too. It would make sense -- if the body senses a stressful environment, which translates to one in which the person is less likely to survive for a long time, it would make sense to get on with the business of passing on one's genes ASAP.
This is from an article in Pediatrics (just found this quote from it, not the full article):
Quote:One theory holds that excess body fat is a kind of reproductive signal that a girl is now healthy enough to sustain a pregnancy. The recent discovery of a fat-cell hormone called leptin "suggests a mechanism by which that might actually happen," Must said.
The second theory rests on skeletal maturity. "We know that children who are overweight have advanced bone development -- they grow faster in all ways, and they are usually taller than their non-overweight peers," Must said. "That same sort of growth promotion could be linked to the early onset of the maturational change."
Interesting....
I'm coming across several refrences to DDE which is a byproduct of DDT and it mimics estrogen. Several studies have apparently linked exposure to DDE to early mensturation.
I don't understand all of the scientific stuff from the sites but maybe one of our medical experts can fill us in.
I haven't a scientific brain cell, so usually stay away from this forum. However, I've done a fair amount of historical reading. I'd be surprised if a bona fide study showed much difference in maturation ages over the last 1 or 2 millenia. There are always flukes in nature, and although they get much attention, it doesn't prove the rule.
Nor can you go by marriageable age as that changes with custom, as Setanta pointed out, and has little to do with nature. But all those historical references of Set's were also of the medieval nobility, where marriage was a business contract between great families. It was far different for the majority of people. Among the yeoman and trader classes, the custom was for women to marry in their late teens or early twenties, much as it is today. This had something to do with the common knowledge that a woman who had menstruated for several years was more likely to bear healthy children, and probably a lot to do with natural instincts when great estates and politics were not involved.
From the data of my own family geneology (a decidedly middle class group, sometimes wealthy, sometimes not) and the anecdotes of my grandmother, I can say that marriage and child-bearing happened in one's early twenties a hundred years ago, on average, and that menstruation started generally between 12 and 15 years of age.
I would question that we are smarter now than our grandparents. Certainly education is more prevalent, and we know more "facts", but smarter -- I'm not convinced. I believe that we are a little taller, due to better nutrition, but the single most important factor in our increased longevity is probably basic hygiene (and the advances in medical science that rest on that).
Well- if you want to get serious I think it is caused by a similar method as that used to force rhubarb. Philip Larkin's famous poem This Be The Verse might give you an inkling.
I think children mature more quickly out of necessity because adults are going backwards and getting more immature every year....
Ok I get the point that you dont necessarily think they're menstruating earlier than a century ago, but what of other types of maturation?
I have read, but can't cite sources that artificial light acting on the pituitary gland (the "'master" gland) has caused girls of the urbanized Western world to mature earlier than girls from rural third world area.
Of course the differences attributed to nutrition would also apply to these groups.
School nurses are expected to deal with menstruation in the elementary schools these days. This was not the case in the '40's and '50's.
My understanding (based on nothing much) is that there are two factors which are probably related.
There have long been reports or commentary, that our water has high levels of estrogen and estrogen-like compounds. I listen for this kind of stuff. Early on people were thinking it was all that medicated (birth control) pee heading into the system with the synthetic hormones taking a long time to decay. Then armchair theorists turned to pvc (pcv?) pipes which ferry water from our houses now having replaced the old lead ones. The plastic/vinyl has estrogen-like compounds in them. Lastly, there was the cow hormones thing. Over-hormoned cows produce milk with elevated hormone levels. We drink a lot of cow milk. By the way, all these things were first noted as the reason why boys seemed to be growing up flabbier and more feminine. <shrug>
The other factor is weight, specifically fat-weight. A few people have spoken of the 90 pound transition. There's a correlation between being 90 pounds and menarch. I imagine that the weight is relative to height and body composition (muscle-fat).
High levels of estrogens and growth hormones in the water can increase fat levels in people, so maybe they're related.
Or.... I could be talking out my patootie again.
and then there's the issue of the hormones that have been in the food chain for the last 40 or so years.
All of this reminds me of the recent link found between young boys using products containing lavender and tea tree oils...
Quote:Jan. 31, 2007 -- Repeated use of products containing lavender oil or tea tree oil may spur breast growth in prepubertal boys, experts report in The New England Journal of Medicine.
<snip>
The tests showed that lavender and tea tree oils may boost estrogen (a sex hormone that promotes female characteristics and is linked to breast development) and hamper androgens (sex hormones that promote male characteristics and inhibit breast growth).
The researchers call for more observational studies to track prepubertal gynecomastia in boys using such products.
link:
http://www.webmd.com/content/article/131/118124
I remember reading an anthropology book that suggested that
later maturation in females was an indication of good health.
I can't find that souce, but here's something to back that up--although this is a stretch totally--from
Ecology and Field Biology :
Quote:Allocation of energy to reproduction is related in part to the nature of mortality, its relationship to population, and predictability of the environment.
Organisms living in an unpredictable environment or subject to heavy environmentally induced mortality tend to allocate a greater proportion of energy to reproduction, to possess single reproduction, and to expand rapidly when conditions are favorable. Such organisms are said to be r-selected because selection favors high productivity.
Organisms which occupy a more predictable environment, are more subject to density-related mortality, tend to allocate less energy to reproduction, and experience repeated reproduction are said to be K-selected because selection favors efficient use of the environment.
So, okay, it's a huge stretch, and according to the book the concept of r- and K- selected "has certain flaws."
I'm just wondering if the principle applies, such as, stress--whether physical or environmental--might produce "early" menstruation in some females, with the idea that their bodies are telling them, they may not live a long life, so they need to reproduce as early as possible to ensure the continuation of the species.
I think our nutrition is worse than ever. The soil has no nutrients in it. It's depleted. Our distribution process further deteriorates the nutrition in the food we grow, because of delays from soil to market, delays that did not exist before, when food was picked and eaten the same day. Vegetables lose 50% of their nutritional value within one--that's one!--quick hour from the soil. And our soil is already depleted. That's why we have to use so much pesticide, our crops are weakened and easy prey for insects and disease.
Not to mention the hormones, the processed foods, etc.
It's a vicious cycle. Anyway, those are my thoughts.
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