[Arleigh]

I would put forth that most "racial" variations of behavior are more due to cultural influences than genetic.

Well, you would be wrong.

Twin studies show that genetics accounts for 97% of variability in fingerprints (duh!); 70% of IQ, 50% of sexual behavior, 50% of criminal activity and 40% of social attitudes.

Average IQ level of blacks is 15 points lower than whites. Average testosterone levels are 10-20% higher in college-age black males than whites. IQ and testosterone levels are key ingredients in behavior among young males.

[Poohbah]

Twin studies show that genetics accounts for 97% of variability in fingerprints (duh!); 70% of IQ, 50% of sexual behavior, 50% of criminal activity and 40% of social attitudes.

Those same twin studies "prove" a genetic link to homosexuality. I question the twin studies that indicate such things, because the famous ones are based on severely flawed models.

Average IQ level of blacks is 15 points lower than whites.

The Stanford-Binet test does presuppose some cultural knowledge. Once you correct for socioeconomic factors, that 15-point gap vanishes to within the MOE.

Average testosterone levels are 10-20% higher in college-age black males than whites.

What was the sample pool for this study? How many blacks versus whites in college are "juicing up" with steroids to compete in sports?

IQ and testosterone levels are key ingredients in behavior among young males.

True enough. However, what factors outside of genetics influence these ingredients?

[Myrddin]

The prison population contains a disproportiate number of "supermales" with XYY genomes. They are less intelligent, more aggressive and have statistically higher criminal tendencies than normal "XY" males.

[ConsistentLibertarian]

The idea of a "social construction" is that there's a real phenomena out there in the world, but that it's there because we believe it is. Example: Money is a social construction. Money really does have value. People will give you things for money. So there's no denying the reality of it. But ... it wouldn't have value unless people believed it did. Apply the analogy to race. There may be real differences between lightly and darkly complected people. The open question has to do with causality. Do our attitudes, beliefs, institutions, etc create those differences or not? Citing more and more evidence of the differences doesn't answer the causal question.

[wardaddy]

Not to mention differences between the tolerance of cold and heat. I have lived and worked the world over in many varied racial cultures/environments. For me to deny that there are at least superficial differences obvious even to my untrained eye would be self denial of my own observations.

[steve-b]

Twin studies show that genetics accounts for... 50% of sexual behavior

I hope you've got your asbestos undies on, now that you've endorsed the reality of the Gay Gene[tm] on FR.

[Sabertooth]

Twin studies show that genetics accounts for... 50% of sexual behavior

If you're referring to a twin study that claims that 50% of the identical twins who are themselves homosexual, have a homosexual twin, there are some serious problems with that study. The first is that the sample population was self-selected by responding to adds in the back of homosexual publications.

Other less-skewed twin studies have given numbers between 10% and 20%.

But there's a problem even calling those 10% to 20% evidence of a genetic link to homosexuality... because the nature vs. nurture debate is a false dilemma. There is a third possibility...

Pre-natal.

Numerous factors can affect pre-natal development. One particulary vulnerable phase occurs when that XY chromosome kicks in the hormones and turns an externally female fetus into the male it was genetically destined to be.

What if pre-natal conditions are somehow less than optimal during that hormone surge? What is the impact on the later sexual preference of that fetus?

We don't really know, but we know that identical twins share an identical pre-natal environment.

Basically, what the twin studies of homosexuals indicates is that the cause is most likely not genetic. Here's why...

Eye color is genetic. 100% of the identical twins with blue eyes have a blue eyed twin. But when twin studies of homosexuality give an identical correlation of 10% or 20% (heck, even 50%), then we know for a fact that homosexuality isn't genetic in 50% to 90% of the cases. The bottom line is that nurture and pre-natal probably account for the bulk of the rest.

After all, wouldn't a "gay gene" have a hard time perpetuating itself?

Hard to escape the fact that homosexuals are absolutely always procreated heterosexually.