I had forgotten that the Bureau of Labor Statistics has been running the National Longitudinal Study of Youth since 1979, and it's still going on, now into a second generation of children of women in the first study, so there is a nationally representative sample of thousands of people for whom we know both their IQs and their mom's IQs, along with a huge amount of detail about their lives and the lives of their mothers. As I wrote in VDARE.com last year:
In 1979, the Bureau of Labor Statistics established a nationally representative sample of about 13,000 young people born from 1957 to 1964. In 1980, the military paid to have the entire sample take its enlistment IQ test, the Armed Forces Qualification Test. In 1990, the NLSY methodically checked up on how they were doing in life. The military provided the data to Charles Murray and Richard J. Herrnstein and it wound up as the centerpiece in the 1994 bestseller The Bell Curve.The NLSY is still going on. It has now even measured the IQs of 6209 children of women in the original panel–2557 of whom were born to black female panelists.
The social scientists keep interviewing the children born to the first generation participants, children who now range in age from new-borns into thirty-somethings, every two years. They typically had their IQs measured twice, first as pre-schoolers, then as 4th or 5th graders. Up through age 14, they were given a school achievement test called the Peabody Individual Achievement Test, and a lot of characteristics were collected about the schools they attended, such as (I believe) phonics versus whole word reading instruction. Here's the official write-up on what info has been collected on the children.
The sample sizes could be large enough to explore the major issue of how good a job California has been doing fostering achievement among public school students compared to the rest of the country.
The data is free and available to the public from here (except for the children's zip codes, which are only available to non-creepy types).