Do upper-middle-class white people just have higher IQs? A Washington Post columnist seems to think so

Is it 1912, or 2012? You'd be forgiven for being confused after reading an op-ed in this week's Washington Post by political scientist Charles Murray who writes that if there's an education gap in our society in which whites are out-performing other groups, it's because students flagging behind are just not smart enough. "(C)hildren’s IQ is tied to that of their parents," Murray writes. "How genes and environment conspire to produce these relationships is irrelevant." Here's the entirety of the offending passage titled Five myths about white people, which was published by the Post Feb. 10:
It’s common to assume that upper-middle-class white kids win more slots in top universities than middle-class or working-class students not because they’re smarter, but because their parents can afford to send them to the best grade schools and high schools, pay for SAT prep courses, or make hefty donations to colleges. There are two problems with this logic. First, ever since the landmark Coleman Report on educational equality back in 1966, scholars have had a hard time demonstrating that attending fancy elementary and secondary schools raises students’ academic performance. And on average, those highly touted test-preparation courses boost students’ SAT scores by only a few dozen points — a finding consistent across rigorous studies of test-prep programs. Second, educational attainment is correlated with intelligence. (The mean IQ of white Americans with just a high school diploma is about 99; the mean IQ of whites with a professional degree is about 125.) And children’s IQ is tied to that of their parents. How genes and environment conspire to produce these relationships is irrelevant; the relationships have been stable for decades. As a result, white parents with advanced educations — who are also generally affluent — inevitably account for a disproportionate number of the white kids with the highest SAT scores, best grades and other evidence of academic excellence. If college admission were purely meritocratic — eliminating favoritism for the children of alumni, celebrities and big donors — upper-middle-class children would still be overrepresented. That’s because the applicants who would be accepted instead would also hail overwhelmingly from the upper middle class
This is not a new position for Murray. His 1994 book "The Bell Curve"  argued that IQ was the main factor in a student's performance. This concept has fallen out of the public's discourse, though, as research about the effect of environmental factors on educational attainment has gained popularity, and legitimacy. Let’s look at some of the differences between two local school districts: Chicago Public Schools and the neighboring Evanston/Skokie CC School District 65. In Chicago, 87 percent of students come from low-income families while in the neighboring Evanston/Skokie district, only 42.9 percent of students come from low-income homes. The website of District 65 boasts class sizes that are smaller than the state average and low student-teacher ratios. Meanwhile, Chicago Public Schools are notorious for being overcrowded. Larger class sizes are only a small part of  what low-income children deal with that may effect their school performance. Parental stress, hunger and physical danger are also part of the day-to-day life for many students living at or below the poverty line. How do the graduation rates of Chicago Public Schools and the Evanston-Skokie district differ? They were, respectively, 58.3 percent in 2011 and 87.1 percent in the year 2009. "We know that early environments and the interactions children are having are what shapes who they become," said Diana Rauner, president of the Ounce of Prevention Fund. "The stress of poor quality education, poor quality childcare are what effect low-income children." The U.S. De