It's certainly a well meaning article, but:

After studying more than 2,000 pairs of twins and administering the Grit Scale, researchers concluded that the hereditability of the two factors contributing to Grit is as follows: Perseverance: 37% Passion: 20%

This idea of quantifying "grit" into separate components with ratios as if it's a freaking cookbook is patently absurd.

I'll throw my general advice into the mix - raising a dog can also help teach young children responsibility, follow-through, and this ephemeral quality "grit".