Scientific evidence on heritability is inconclusive at this point, from what I understand, there was a recent article on this http://online.wsj.com/article/SB1000142412788732416230457830...?

"People have chosen to ignore the genetics of intelligence for a long time," said Mr. Zhao, who hopes to publish his team's initial findings this summer. "People believe it's a controversial topic, especially in the West. That's not the case in China," where IQ studies are regarded more as a scientific challenge and therefore are easier to fund.

The Wikipedia article pointed to [1] cites the heritability of IQ from 0.5 to 0.9, settling in between 0.75 and 0.85. I had always believed it to be 0.5 and was surprised at how heritable IQ is, with 57% to 73% of offspring intelligence being explicable by the parents' IQs. Note that "job performance, income, and literacy" are predicted, to varying degrees, by childhood IQ.

[1] https://en.wikipedia.org/wiki/Heritability_of_IQ

> Wow, they go through this whole spiel without even asking the question of whether or not IQ is hereditary.

But they do ask exactly that.

That was my first thought - when I read "IQ" I already hit the back button. Genes alone are not enough to explain _anything_ - Gene expression, influenced by upbringing, environmental factors etc., better hits the target.

Studies of twins consistently show a heritability of about 85% for adult IQ and executive function (focus vs. ADHD). The postnatal environment has little effect unless it is severely neglectful or deprived.

Edit: added "postnatal".

Do these twins grow up in comparable environments? Another thing to consider: gene expression and brain development is kicked off in the womb, and twins most often share the same mother. I'm not sure your argument applies here.

That's the point of twin studies: comparing genetically identical subjects who grew up in different environments.

The prenatal influence cannot, practically, be investigated at this point in history.

The prenatal influence has been directly tested. They compare pairs of non-identical siblings, some who are twins and some who are not. The same pregnancy pairs are about as similar to each other as the other pairs. So the prenatal environment either has little effect, or it has a significant but highly nonlinear effect. (Once again, this assumes no extreme hardship.)

Interesting, thanks.

Some of the studies use twins raised in the same household, some use twins adopted by different families. They get very similar results.

Although you believe this is the case, a family should be allowed to select what they view as the "best" donor possible