&gt; If a CRISPR change doesn&#x27;t kill you, it seems to me unlikely to kill your offspring.<p>I don&#x27;t think that&#x27;s a justifiable conclusion.<p>&gt; This may be naive, I don&#x27;t know to what extent a gene variant would be fine in an adult but not fine in a child.<p>There are lots of genes that have wildly varying effects at different developmental stages (and even under different environmental conditions at similar developmental stages.)<p>There are also genes that have different effects in homozygous, heterozygous, and hemizygous arrangements, on which a parent and child might differ.