The participation of children in clinical research requires parental permission. We designed this study to evaluate the extent to which the risk associated with a clinical study affects the parents' decision to provide permission. Simultaneously, we evaluated factors which led parents to allow or decline their child's participation in such clinical studies.

We interviewed 82 parents of children of ASA class I-II scheduled to receive general anesthesia for elective surgery. Parents were presented with either of two sham protocols: no risk (Control, n = 44), or pain (Pain, n = 38) and asked to complete a questionnaire detailing the reasons for their decision.

There were no differences in the demographics of the two groups. Whereas comprehension of the doctor's explanation was similar in both groups, consenting rates were higher in the control group (54.5% versus 28.7%; P < 0.01). The importance of the study was the primary factor in the parents' decision to consent, and the child's safety was the main concern for parents that declined. Only 4.2% of the control group and 3.7% of the risk group reported having felt pressured to consent.

Results of this study show that the contents of study itself is an important factor that influences a parent's decision to consent to a child's participation in clinical studies. Therefore it is important that researchers produce an adequate protocol and a reasonable explanation for obtaining consent, to reduce the potential for selection bias, and to ensure that the legal and ethical rights of patients are protected.