A rule of thumb seems to be that genetic effects tend to be roughly twice as impactful as that of nurture in determining differences in social outcomes.

A worthwhile gathering of evidence in Where parents make a difference by Inquisitive Bird.  The subheading is Where is the shared environment effect larger than zero?

IB is exploring the phenomenon of intellectual extremism associated with the Nature versus Nurture debate as to which is more important - Genes (and IQ) or Sociology (and Parents).  Back in the 1980s, Judith Harris launched a slow-growing attack on the then prevalent idea that a child's success was rooted in parenting.  Her argument was that yes, society is important but that it was the non-shared aspect of childhood (friends and the broader social environment) rather than the shared environment (the family.)

This often got summarized as parents don't matter.  Which is inherent bunk.

On the other extreme, there are those who do make a strong argument that it is all in the genes, IQ certainly, but other attributes as well (health, height, BMI, etc.), and even behaviors.

The argument has alway been overly polarized and IB is pointing out that this is not an either-or issue.  Genes matter and Shared Environment matter.  The former probably twice as much as the latter, but both critically important.  

Common interpretation errors

In discussions related to this issue, there are a few common interpretation errors that I think are worth addressing right off the bat:

Dismissal of “small” variance components. When the shared effect is estimated to be, say, 5% or 10%, these effects are often dismissed as negligible. But when we discuss social outcomes — which are influenced by many factors, each of small relative effect — such effects are by no means trivial or unimportant, even if they are smaller than the effect of genetics.1

Properly comparing effects. When we wish to compare the relative effects of additive genetics (a²) and the shared environment (c²), we need to square root them (see, e.g., Del Guidice, 2021). For example, if heritability is 40% and shared environment 10%, then the effect of genes is twice as large as that of the shared environment effect, not four times [√(0.40)/√(0.10) = 2]. A factor 2 difference is substantial, but not so large it makes sense to call one effect big and the other negligible.

Lack of power, and statistical insignificance does not imply zero difference. The assertion of “0% shared environment” is typically just a lack of statistical power, where the component is not significantly different from 0. But that does not mean the best point estimate is 0%. For example, the idea that identical twins reared apart (MZA) are as similar as identical twins reared together (MZT) is very likely just the consequence of MZA samples being too small to reliably tease out small but real differences in correlations (though large enough to confirm the importance of genetics).

[snip]

There are many people who overestimate the effect parents have on children’s outcomes. If you observe an association between parent and offspring and naively interpret that as simply the effect of parenting (“the nurture assumption”), you’re making a mistake. In all likelihood, genetic transmission accounts for a large fraction of that association.

The Second Law of Behavior Genetics states: the effect of being raised in the same family is smaller than the effect of genes (Turkheimer, 2000). I don’t make the slightest claim to overturn this law. The evidence I've reviewed, summarized in the table below, is very much consistent with it. But a² > c² and c² = 0 are very different statements. A rule of thumb seems to be that genetic effects tend to be roughly twice as impactful as that of nurture in determining differences in social outcomes.