Answer:
The research must pose no more than minimal risk.
Explanation:
In research, minimal risk refers to the type of risk that only expose the subjects with very little level of discomfort. Typically, this type of risk is required for test subjects who haven't entered adulthood.
Children specifically, still haven't experience perfect development in both of their physiques and brain capacity. This make them became extremely vulnerable for scientific experiments. One single mistake could destroy the rest of their life.
This is why before the researchers even think about asking permission to their parents, they need to ensure that every procedures in the research only pose no more than minimal risk.