“Interestingly, girls who live in warm climates begin their periods earlier than girls who live in colder ones. This suggests that it is the warm weather or increased exposure to sunlight that initiates earlier growth and menstruation. Some theorists even believe that exposure to light (including electric light) is the reason that girls presently reach adolescence earlier than their great-great grandmother’s generations.”
Well, both of my daughters went through precocious puberty and none of the reasons given above had a thing to do with it. They don’t like meat, are both on the thin side, and will be very short because of the early puberty. The 11- year-old has been menstruating for 2 years and has a bone age of 15, thus her growth has almost topped out at 4’11".
They aren’t exposed to foods with hormones, they aren’t overweight, and yet they both went through puberty at the age of 8.
My MIL also started puberty early, menstruating by 10, so I think it’s pure genetics in our case.
I can only go by what it was like, when I reached puberty, at age 12, in 1973. Girls were reaching puberty at the same age.
I think we notice it today, because teens of today are more outspoken, more self assured. And the fashion these young teen girls wear, makes us notice that they are indeed maturing. We see 13 y.o. girls with Wonder Bra, bare stomach and tight hotpants, with an attitude worthy of a high school senior, we’re gonna think the changes are coming earlier. My WAG is that they’re not. We just notice it, 'cause they’re showing it. Sadly, so.
The line that provides the 17 years in 1830 figure is perfectly straight, and looks like a pretty poor attempt at regression to my eye. As the site that you cited itself mentions,
In any case, I’d be dubious of that figure solely on the basis of my (limited) exposure to the historical record of various cultures. As far as I can recall, most non-industrialized cultures, either in the past or in the modern world, practiced marriage and reproduction at a much younger age than is the current norm in our society. I believe that it’s a safe generalization to state that, across historical cultures (ie., ancient Egyptian, Greek, Roman, Chinese, medieval European, etc.) girls were generally married off around 13 or so, when they became “women” (reached menarche), to older (16/17 yo.) men.
Naturally, I’m too lazy to go track down any cites for this, but hopefully someone with a bit more motivation will come along if anyone has issues with my grand historical generalization.
[Disclaimer] The above was solely representative of the dumb roomie, and should not be read as an endorsement of said views by Eonwe. Though I’m pretty sure he’d back me up were he here right now.[/Disclaimer]
Perhaps I might carry a little more credibility were I smart enough to remember log out of my roommate’s profile and post under my own name. I think I’ll go back to lurking now.
It looks as though there may be a data point at 1830, which makes your argument about extrapolation irrelevant. I agree though that the plot is suspiciously linear. My main point in posting the link was to show that there actually is is data on the phenomena.
The perfectly straight nature of the line to get to 1830 makes me suspect that the data point might be purely of a cosmetic nature in an attempt to hide some poor fudging of data. But that’s neither here nor there. I agree with you that there is, indeed, data that supports a decrease in the average age of menarche. I was simply attempting to indicate that your chosen site and cite might not have been the best support for your argument.
“I believe that it’s a safe generalization to state that, across historical cultures (ie., ancient Egyptian, Greek, Roman, Chinese, medieval European, etc.) girls were generally married off around 13 or so, when they became “women” (reached menarche), to older (16/17 yo.) men.”
I can think of one society where females are not considered marriageable until they have produced at least one child and many where they are marriageable well before puberty.
Do you have any data to support your assertion that in ancient Egyptian, Greek, Roman, Chinese, medieval European, and other cultures girls were generally married off WHEN they reached menarche (in contrast to well before or well after they reached menarche)?
Where the heck did I hear this? Don’t remember, but here it goes. IIRC girls will start meanstruating when their body weight reaches 105 lbs. The improved nutrition/medicine/etc of the 20th century brought the agen when that happens down, but the average age for menarche has not changed much since the mid 20th century.
In Acrobat Reader 5.0, on the Basic Tools bar, there is a button that looks like a capital T with a little rectangle beside it. This is the text select tool, and will let you highlight text in a PDF file so you can copy it to the clipboard. Other versions of Reader have a similar feature, but I can’t recall whether you access it the same way.
Oh I see. Why would anyone want to view PDFs from within the browser? I thought this was one of those features that comes by default, which everyone would just turn off. Like Explorer’s “Hide extensions for known file types” setting. It’s strange enough that the setting is there, but I’m baffled why it’s the default.
By the way, you can turn this off by starting Acrobat Reader, then Edit, Preferences, Options, and un-checking “Display PDF in browser”.
If you encounter a site that is in PDF and want to view in HTML, just enter the sites address into Google and there will be a link titled ‘View as HTML’ and if you click on that, Google will direct you to a cached HTML version of the site.
[url=http://www.bio.ic.ac.uk/research/iowens/pdf%20of%20%20papers/Kirk%20et%20al%202001%20Evolution.pdf]HTML of liink provided]
