confidence level: I am a physicist, not a biologist, so don’t take this the account of a domain level expert. But this is really basic stuff, and is very easy to verify. Recently I encountered a scientific claim about biology, made by Eliezer Yudkowsky. I searched around for the source of the claim, and found that he has been repeating versions of the claim for over a decade and a half, including in “the sequences” and his TED talk. In recent years, this claim has primarily been used as an argument for why an AGI attack would be extremely deadly. I believe this claim is factually incorrect.
Yudkowsky:
Multiple commenters on FanFiction.net replying to chapter 23 of HPMOR: Genetics don’t work that way. If magic were recessive, then wizard parents would always have wizard kids and there would be no such thing as squibs. Look, I drew the Punnett square…
Don’t patronize fans, Yud.