One thing I've always wondered - at what age are Indian kids (or kids from other cultures with spicy cuisines) introduced to spicy food? They mention kimchi for toddlers in the article, what about in India?
The first solids one of my kids (UK) had was Thai green curry, at 5 months, but it wasn't very spicy. Our kids just ate what we eat when they were ready to ween [move on to solid foods]; I can imagine this is probably quite common and so in many cultures if the adults are eating spicy food then the kids are from the time they begin to ween.
(speaking as a South Indian).