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I was also interested and did a quick Google search and found a few different results:

Male-to-Female Transsexuals Have Female Neuron Numbers in a Limbic Nucleus

White matter microstructure in female to male transsexuals before cross-sex hormonal treatment. A diffusion tensor imaging study.

It seems as though there are some differences in the brain for transgendered individuals in that areas of their brain are more similar to the gender that they think they are rather than the brain of the gender that typically corresponds with their biological sex. It also appears (at least from these studies) that hormone therapy is not responsible for those changes. There isn't anything to suggest what causes this to occur, so it could be biological or social, but I doubt it would be largely due to social causes as that would seem to imply that people could become far more intelligent simply by acting like a genius. At the same time, I don't think it's genetic (or entirely so) either as it intuitively seems as though being transgendered probably produces a less fit individual as I can't imagine having to cope with your brain telling you that you're in the wrong body for your whole life making life easier, especially if everyone else treats you as though you're insane.

Simon LeVay also published some similar research about 20 years ago that examined differences in the brains of homosexual and heterosexual men, so some of that research might also provide some insight into what might cause the observed differences.

You're so right, English farce comedy from the '70s is definitely authoritative on this topic.
Go on, quote a bible verse next.

http://jcem.endojournals.org/content/85/5/2034.full - Do you have any brain anatomy which is more characteristic of an aardvark than of a human?

Actually, from your demonstrated logic skills, it sounds as though you just might. Cerebus it is, my otherkin friend.

Weight loss rebound only happens to people who are fat already. It's not a problem that anorexics face.

This is simply not true. There are many people (mostly but not exclusively young women) of normal weight who starve themselves in an attempt to become extremely thin, and then become obese afterward. And obese people often become more obsese after such a cycle. That's just the way the biology works; starvation creates major changes in metabolism. If you're interested, here is one of many, many references on this phenomenon.

And other than idiots like yourself who think theres something wrong with it, what exactly is the problem going to be with this happening?

You have some evidence this is settled science?

...isn't it a medicinal fact that they reach puberty earlier than say.. 20 years ago?

Eh... its a hypothesis. There is strong evidence that in the U.S., girls begin puberty earlier than a generation ago, as measured by breast development or change in height, but their first periods are not earlier [2001]. And while environmental and social factors may have an effect, these are small compared to individual variation [2003], and there does not seem to be a change in onset of puberty in Europe. A sure way to delay puberty, though, is to be malnourished.

I was in a study about nine years ago in which I was given norplant implants plus weekly testosterone injections. (I think I was in Group 4 of this study or a very similar one.) The injections were annoying but not painful; I self-injected in large leg muscles (front or back). It was effective (my sperm count went to zero) and reversible (we conceived without difficulty a year or so later).

HOWEVER, the effect on my mood was not pleasant. To me, it seemed like the world was a less reasonable place. To others, it seemed like I was more irritable and less fun to be around. I don't recommend the experience!

Maybe you should have spent five minutes with Google before shooting your mouth off about something you're obviously clueless about. Putting aside the sheer stupidity of claiming that subjective states such as hunger or gender dysphoria don't exist because you can't directly observe them, it just isn't true that you're speaking of a subjective state with no independently observable correlates:

Male-to-Female Transsexuals Have Female Neuron Numbers in a Limbic Nucleus

According to this study, these interpolations may be inaccurate or lacking of additional variables such as people's TEE limited by their poor fitness. In other words, it seems you increase your energy expenditure only if you used to be a lazy slob. Otherwise, the major source of calorie burning comes from the direct cost of energy from the specific workout itself.

I think this makes sense in an evolutionary sense, otherwise individuals that had to sweat to hunt would have eventually had to hunt more to satisfy their growing need for energy. Instead, the body got stronger and more efficient at handling the current caloric input.

Grrr. Bloody Slashdot made my comment illegible. Re-posted with non-broken formatting:

I know I'm going to regret debating gender with an anonymous coward on Slashdot, but referring to trans women as "transgenderred [sic] males" is just a little too offensive to let pass. There's good evidence to suggest that transsexualism is caused by congenital differences in certain parts of the brain involved with gender identity and sexuality [1] [2]. Essentially, we really are born with female brains. There's also evidence to suggest that a number of anatomical features of our brains shift to opposite-sex proportions during the first few months on hormones [3].

As for your ideas on explaining the sex ratio in technology jobs by men having a wider IQ distribution than women, I just don't think the numbers hold up. While there seems to be some support for men's IQ distribution having a larger standard deviation than women's, it just isn't enough to support your claim that "the chance of a person having an IQ of 125 is eight times more likely for males than females." The idea certainly isn't an implaausible one at extremely high IQ scores; all it would take would be an X-linked trait that sufficiently influences IQ for people with XY chromosomes (mostly masculine-gendered) to have a wider distribution than people with XX chromosomes (mostly feminine-gendered), and XY people *do* have a wider range of variation on a lot of different traits, probably because of a mechanism like this.

The problem is that the effect would be just too small to make that big a difference; some quick googling turned up at most support for a one or two point difference in standard deviation, and that certainly wouldn't lead to a factor of eight difference at scores as low as 125. A one point difference in male versus female standard deviation of IQ in a population with an overall standard deviation of 16 points leads to men being twice as likely as women to have an IQ over 150, and only one person in a thousand of either sex scores that high. No matter what inflated opinions Slashdotters might have of themselves, I can say very assuredly that the great majority of IT workers do not have 150+ IQs. This sort of theory is probably only useful for explaining sex ratios in elite groups like Nobel prize winners, and I'd be rather skeptical even then of the assumption that the distribution of extremely high IQ scores can be obtained just by extrapolating the distribution for the middle-scoring bulk of the population.

[1] A Sex Difference in the Human Brain and its Relation to Transsexuality

[2] Male-to-Female Transsexuals Have Female Neuron Numbers in a Limbic Nucleus

[3] Changing your sex changes your brain: influences of testosterone and estrogen on adult human brain structure

I know I'm going to regret debating gender with an anonymous coward on Slashdot, but referring to trans women as "transgenderred [sic] males" is just a little too offensive to let pass. There's good evidence to suggest that transsexualism is caused by congenital differences in certain parts of the brain involved with gender identity and sexuality [1] [2]. Essentially, we really are born with female brains. There's also evidence to suggest that a number of anatomical features of our brains shift to opposite-sex proportions during the first few months on hormones [3]. As for your ideas on explaining the sex ratio in technology jobs by men having a wider IQ distribution than women, I just don't think the numbers hold up. While there seems to be some support for men's IQ distribution having a larger standard deviation than women's, it just isn't enough to support your claim that "the chance of a person having an IQ of 125 is eight times more likely for males than females." The idea certainly isn't an implaausible one at extremely high IQ scores; all it would take would be an X-linked trait that sufficiently influences IQ for people with XY chromosomes (mostly masculine-gendered) to have a wider distribution than people with XX chromosomes (mostly feminine-gendered), and XY people *do* have a wider range of variation on a lot of different traits, probably because of a mechanism like this. The problem is that the effect would be just too small to make that big a difference; some quick googling turned up at most support for a one or two point difference in standard deviation, and that certainly wouldn't lead to a factor of eight difference at scores as low as 125. A one point difference in male versus female standard deviation of IQ in a population with an overall standard deviation of 16 points leads to men being twice as likely as women to have an IQ over 150, and only one person in a thousand of either sex scores that high. No matter what inflated opinions Slashdotters might have of themselves, I can say very assuredly that the great majority of IT workers do not have 150+ IQs. This sort of theory is probably only useful for explaining sex ratios in elite groups like Nobel prize winners, and I'd be rather skeptical even then of the assumption that the distribution of extremely high IQ scores can be obtained just by extrapolating the distribution for the middle-scoring bulk of the population. [1] A Sex Difference in the Human Brain and its Relation to Transsexuality [2] Male-to-Female Transsexuals Have Female Neuron Numbers in a Limbic Nucleus. [3] Changing your sex changes your brain: influences of testosterone and estrogen on adult human brain structure

All sugars promote tooth decay.

Also http://www.medicalnewstoday.com/medicalnews.php?ne wsid=65470, http://jcem.endojournals.org/cgi/content/full/89/6 /2963, http://www.sciencedaily.com/releases/2005/05/05050 3152956.htm

Fructose depresses leptin and insulin levels. Leptin is normally produced when you eat, and this triggers the "ok, I'm no longer hungry" signal in your brain so you stop eating. Lowering the leptin level causes you to still feel hungry, even after you've eaten. Switching from fructose to sucrose will allow your body to regulate itself better.

Its probably going to take some major lawsuits (and bankruptcies) to fix this problem ...

It appears that D3 is used far more efficiently by the human body than D2. There may be some issues with D3 used by other, minor metabolic pathways that make D3 healthier. Note D3 is the form produced by the human body on exposure to UV light. http://jcem.endojournals.org/cgi/content/abstract/ 89/11/5387 It appears D2 is about 1/3 the effective dose as the same quantity of D3.

Chicks dig it when you read the primary sources.

BTW, always ask who paid for the study. In this case, it's the National Institutes of Health (not the Testosterone Salesmen of America). That's why they have to post the manuscript free online.

http://jcem.endojournals.org/cgi/content/abstract/ jc.2006-1375v1

This version published online on October 24, 2006
Journal of Clinical Endocrinology & Metabolism, doi:10.1210/jc.2006-1375

A population-level decline in serum testosterone levels in American men
Thomas G Travison*, Andre B Araujo, Amy B O'Donnell, Varant Kupelian, and John B McKinlay

New England Research Institutes, Watertown, MA, USA

Context. Age-specific estimates of mean testosterone (T) concentrations appear to vary by year of observation and by birth cohort, and estimates of longitudinal declines in T typically outstrip cross-sectional decreases. These observations motivate a hypothesis of a population-level decrease in T over calendar time, independent of chronologic aging.

Objective. To establish the magnitude of population-level changes in serum T concentrations, and the degree to which they are explained by secular changes in relative weight and other factors.

Design. A prospective cohort study of health and endocrine functioning in randomly selected men of age 45-79 y. Three data collection waves: baseline (T1: 1987-89) and two follow-ups (T2: 1995-97, T3: 2002-04).

Setting. An observational study of randomly selected men residing in greater Boston, MA, USA.

Participants. Data obtained on 1374, 906 and 489 men at T1, T2, and T3, respectively, totaling 2769 observations taken on 1532 men.

Main outcome measures. Serum total testosterone and calculated bioavailable testosterone.

Results. We observe a substantial age-independent decline in T that does not appear to be attributable to observed changes in explanatory factors, including health and lifestyle characteristics such as smoking and obesity. The estimated population-level declines are greater in magnitude than the cross-sectional declines in T typically associated with age.

Conclusions. These results indicate that recent years have seen a substantial, and as yet unrecognized, age-independent population-level decrease in T in American men, potentially due to birth cohort differences or to health or environmental effects not captured in observed data.

Real nerds read the meeting abstracts:

5th World Congress on the Aging Male, Salzburg, Austria, February 9-12, 2006
http://www.kenes.com/aging/aging5/index.asp

While I am involved in biology, I've never personally encountered temporal transcription regulation. A quick Google Scholar search shows that quite a few examples have been demonstrated: "temporal transcription regulation" search".

The first result, this paper, shows a pretty cool example of a protein changing behavior depending on whether it's exposed in a pulsatile or continuous manner to growth hormone. That's from 1997, so not too recently.

His assertion that gender identity is a "choice" rather than an endowment is neatly contradicted by the relevant scientific disciplines. GENDER IDENTITY IS NOT A CHOICE. Gender EXPRESSION is a choice; nevertheless, you cannot "choose" if you want to feel like a man or a woman.

I am transsexual myself. I am a registered SlashDot user, but because of the widespread public prejudices and misconceptions (e.g. that we are all gay, cross-dressers, "faggots", "sinners", etc.) I am posting anonymously.

Gender identity is fixed in the brain (specifically, in the hypothalamus) prior to birth, or at some point in the very first years of life. (I'm talking maybe the first three or four, not the first twenty or thirty.) Scientists studying the brains of deceased transsexuals have found that male-to-female transsexuals possess FEMALE brain structures. Likewise, female-to-male transsexuals possess MALE brain structures. These structures are intrinsic to the makeup of the brain itself-- and cannot be altered. They were present regardless of whether or not the subject underwent any sort of transgendered therapy-- e.g. taking hormones, having a "sex change", etc. Again, these structures are fixed and unchangeable. The position of anyone who feels that gender identity (for example, in the case of transsexuals) can be "changed" (excepting through extreme brainwashing) is as untenable and scientifically bogus as those who feel that gay people can be "cured" of their sexual orientation. Incidentally, please note that sexual orientation and gender identity are different things altogether. Transexuals can be gay (or lesbian), straight, bi, or even asexual, just like anyone else. Think of sexual orientation as the "x axis" and gender identity as the "y axis". You can be at any point in that system.

The only "choice" a transsexual has is whether or not they choose to act on their inner needs and undergo "transition". Gender identity, in no cases (whether a transsexual or a "normal" person) is a choice. You can no more "choose" to be male or female inside (i.e. in your brain, where gender feelings originate) than you can "choose" to be smart, or dumb, or right-handed, or left-handed. It's something you're born with. So, yes, gender identity IS an endowment. However, it doesn't necessarily always coincide with one's genitalia.

In case you doubt me, please read the following entries from reputable scientific journals:

ARTICLE #1
ARTICLE #2

This is NOT a matter of "opinion". You cannot "feel" that atoms don't exist. You cannot "feel" that 2 + 2 makes 27.5. You likewise cannot "feel" that gender identity is a choice. It is simply not so. Science has demonstrated this quite clearly.