Final answer:
The responsibility of determining whether children can assent to a research trial lies with the Institutional Review Board (IRB), which ensures their protection and informed consent through detailed processes.
Step-by-step explanation:
Who is responsible for determining whether children are capable of assenting to participate in a research trial? The primary responsibility lies with the Institutional Review Board (IRB) of the research institution conducting the trial. Parents or legal guardians are required to provide consent on behalf of their children, as children by themselves are not considered competent to consent. The IRB ensures that all research participants, including children, are adequately protected through the informed consent process which outlines the risks and benefits of the study and confirms that participation is voluntary. It also guards the principle of autonomy by ensuring that potential participants are fully informed to make a decision about their involvement in the trial.