Why does everyone find much stronger genetic effects than parental in adoption studies?
“Little intergenerational correlation in education was observed in the absence of genetic similarity between parent and child—that is, among adoptees.”
“By examining parent-offspring resemblance in a sample of offspring that are among the oldest of any adoption study of IQ to date, we have effectively tested for the presence of parenting effects that would have persisted for more than a decade after the conclusion of the typical rearing period. No such persistence is found to occur in our unique sample.”
“Little intergenerational correlation in education was observed in the absence of genetic similarity between parent and child—that is, among adoptees.”
https://gwern.net/docs/genetics/heritable/adoption/2021-lude...
“By examining parent-offspring resemblance in a sample of offspring that are among the oldest of any adoption study of IQ to date, we have effectively tested for the presence of parenting effects that would have persisted for more than a decade after the conclusion of the typical rearing period. No such persistence is found to occur in our unique sample.”
https://gwern.net/docs/iq/2021-willoughby.pdf
In an adoptive sample of Korean Americans parental income was unrelated to offspring income.
https://gwern.net/docs/genetics/heritable/adoption/2007-sace...