"is my child good at it?"
"is my child talented enough in chess?"
or worst of all,
"is my child gifted in chess?"
As I understand, they don't want to waste any time or money on something their child can't be an outstanding achiever. They ask such questions after a few lessons, or after couple of months of learning, or after a few tournaments, sometime even before their child starts to learn chess. They want to make their decision early and quickly.
Several bad things might happen if they keep brooding on such questions, even if their child is really talented. The child may not start to learn chess at all, if the parents can't see any potential. The child and parents may easily get discouraged when the initial progress is slow. Their doubt will grow over-sized large with the passing time, and they will quickly quit. They will switch to other activities, asking the same questions and getting the same results.
There is a parable about a well digger, who tried to dig a well in a desert. He dug a little bit, could not find water, then he stopped, moved some distance and started to dig again. After leaving hundreds of holes on the ground, he still could not find any water, because none of them was deep enough.
It's not easy to see talent if the child is a slow starter. A special event or moment may be required for him/her to get on the right track. Even if s/he is talented, it takes a lot of hard work to become a great achiever, according to 10,000-hour rule. Gifted or not, without hard work, no one will become a genius. Without firm belief in oneself and full support from parents, no one can perseveres through 10,000 hours. Most will hesitate and stop when the road becomes bumpy.
Like many other activities, chess has numerous benefits for the child even if s/he can't become a GM. Therefore, don't ask such negative questions. Just follow Nike's slogan: JUST DO IT.