smart people saying stupid things

From a piece on impossible experiments:

Musical Storks
I would collect all newborn babies and randomly reassign them to new parents. I’m confident that we will confirm the 50-0-50 rule: Adult personality is roughly 50% genetic, 0% how they are raised by their parents, and 50% socialization outside the family by peers and friends.

Said by an evolutionary psychologist, who one would hope knows about these things. But 0% influence from parental upbringing? Really?

Some defence of the notion in this summary of a book where the idea apparently originated but I don’t find it convincing.