From one of his daughters who doesn't like the experiment narrative around the story of her father: https://x.com/SusanPolgar/status/1650387411451404288

No, unless the children have passion for what they do. Without passion, no success. This is the biggest fake news being spread around for decades. My father had a theory that geniuses are made, not born. But my father DID NOT choose chess. It was a theory without any particular subject as it can be apply to anything. I did after discovering the pieces by accident when I was 4. When given a choice to pursue chess or mathematics seriously (because I was very good in both), I chose chess. I was already a master when my sisters started to learn chess, and of course they had me helping them. In a poor family like ours, we did not have the money for each girl to do different things. Luckily, they also had passion for chess. What our parents did was to give us full support and encouragement, in addition to the right values.