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I wouldn't believe that part about biological reasons, people started having sex a lot earlier a few hundred years ago (when people die at 30, they'd better), in spite of the fact that they hit puberty later because of undernourishment.

Still, I read something the other day, that people on average start having sex at 16-17, and that only one in ten have had sex at age 14. Which is probably why everyone felt that they were the only one who hadn't had sex when they were 14.

Peak oil is not an energy crisis. It is a liquid fuel crisis.

by Starvid (arvid.hallen at gmail.com) on Fri Nov 6th, 2009 at 02:34:58 AM EST
[ Parent ]
Did they really hit puberty later?
Indian girls hit puberty earlier than European ones, yet are less nourished.

Maybe it's pollution? Maybe social changes lead the brain to delay it. I don't really know, but so far I had only ever read that people used to hit puberty younger in the past.

Earth provides enough to satisfy every man's need, but not every man's greed. Gandhi

by Cyrille (cyrillev domain yahoo.fr) on Fri Nov 6th, 2009 at 03:34:30 AM EST
[ Parent ]
Timing of the onset of puberty

The definition of the onset of puberty depends on perspective (e.g., hormonal versus physical) and purpose (establishing population normal standards, clinical care of early or late pubescent individuals, etc.) The most commonly used definition of the onset of puberty is physical changes to a person's body[citation needed]. These physical changes are the first visible signs of neural, hormonal, and gonadal function changes.

The age at which puberty begins varies between individuals and populations. The age at which puberty begins is affected by both genetic factors and by environmental factors such as nutritional state and social circumstances.[1]

The average age at which puberty begins is affected by your race. For example, the average age of menarche in various populations surveyed[weasel words] has ranged from 12 to 18 years. The earliest average onset of puberty is for African-American girls and the oldest average onset for high altitude subsistence populations in Asia. However, much of the higher age averages reflect nutritional limitations more than genetic differences and can change within a few generations with a substantial change in diet. The median age of menarche for a population may be an index of the proportion of undernourished girls in the population, and the width of the spread may reflect unevenness of wealth and food distribution in a population.

Researchers have identified an earlier age of the onset of puberty. However, they have based their conclusions on a comparison of data from 1999 with data from 1969. In the earlier example, the sample population was based on a small sample of white girls (200, from Britain). The later study identified as puberty as occurring in 48% of African-American girls by age nine, and 12% of white girls by that age.[34]
Historical shift

The average age at which the onset of puberty occurs has dropped significantly since the 1840s.[35][36][37] Researchers[who?] refer to this drop as the 'secular trend'. In every decade from 1840 to 1950 there was a drop of four months in the average age of menarche among Western European females. In Norway, girls born in 1840 had their menarche at an average age of 17 years. In France the average in 1840 was 15.3 years. In England the average in 1840 was 16.5 years. In Japan the decline happened later and was then more rapid: from 1945 to 1975 in Japan there was a drop of 11 months per decade.



Peak oil is not an energy crisis. It is a liquid fuel crisis.
by Starvid (arvid.hallen at gmail.com) on Fri Nov 6th, 2009 at 03:46:31 AM EST
[ Parent ]
A range from "African-American girls" to "high altitude subsistence populations in Asia"  -- and it did not occur to the Wikipedia author that race is unlikely to be the factor here?...

*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Fri Nov 6th, 2009 at 04:27:08 AM EST
[ Parent ]
Both race and nutrition is a factor. That becomes apparent when you compare black and while american girls.

But I guess no one should be surprised when something is influenced both bu genes and the local environment, after all, what isn't?

Peak oil is not an energy crisis. It is a liquid fuel crisis.

by Starvid (arvid.hallen at gmail.com) on Fri Nov 6th, 2009 at 04:14:10 PM EST
[ Parent ]
compare black and while american girls

How do you separate the effect of genes and different social situations?...

*Lunatic*, n.
One whose delusions are out of fashion.

by DoDo on Fri Nov 6th, 2009 at 06:57:44 PM EST
[ Parent ]
By comparing people in the same social situation.

Peak oil is not an energy crisis. It is a liquid fuel crisis.
by Starvid (arvid.hallen at gmail.com) on Sun Nov 8th, 2009 at 03:17:35 PM EST
[ Parent ]
Multivariate regression...

En un viejo país ineficiente, algo así como España entre dos guerras civiles, poseer una casa y poca hacienda y memoria ninguna. -- Gil de Biedma
by Migeru (migeru at eurotrib dot com) on Sun Nov 8th, 2009 at 03:37:46 PM EST
[ Parent ]
You don't do that by simly comparing "black and while american girls" -- not to mention black merican girls and "high altitude subsistence populations in Asia".

*Lunatic*, n.
One whose delusions are out of fashion.
by DoDo on Mon Nov 9th, 2009 at 04:53:58 AM EST
[ Parent ]
Starvid:
people started having sex a lot earlier a few hundred years ago (when people die at 30, they'd better)

Where did you get that from? Do you mean people started having sex before puberty?

As for "when people die at 30", that's a common misunderstanding of life expectancy at birth statistics. Life expectancy at birth of 40 (the most common figure quoted for Early Modern Europe) does not mean everyone dies at 40. It's an average, and the reason it's so low is infantile mortality. At birth, you had a fairly high chance of dying in the first week of life, (first year, first ten years). But if you got through to 30 you had a decent chance of reaching 60 or 70.

by afew (afew(a in a circle)eurotrib_dot_com) on Fri Nov 6th, 2009 at 03:59:28 AM EST
[ Parent ]
Where did you get that from? Do you mean people started having sex before puberty?

No, that wouldn't make much sense, would it? But certainly earlier than the current 17. IIRC the age of consent was considerable lower in the olden days, in spite of people hitting puberty later than they do today, because of worse nutrition.

Peak oil is not an energy crisis. It is a liquid fuel crisis.

by Starvid (arvid.hallen at gmail.com) on Fri Nov 6th, 2009 at 04:09:32 AM EST
[ Parent ]

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