Clinical trials are required in order to develop new treatments and improve both patient life expectancy and quality of life. In this respect the last 10 years proved their efficiency. However clinical research shows one of the most difficult dilemmas from an ethical point of view. Patients included in clinical trials are submitted to known and unknown risks and hazards, but rarely benefit from the results. This is even more evident when clinical trials use children who are terminally ill. The core consideration becomes how far should we go with research when considering the child best interest.