While the advantages of research involving child subjects are usually uncontested on medical grounds, many question such research on moral grounds. The ethics of conducting research using human subjects rest on informed consent, which infants and young children can never be sufficiently mature to provide.
No parent or guardian, even with the best intentions, has the moral status to consent for a child to be made the subject of medical investigation. Even if this severely restricts possible advances in childhood medicine, the moral progress of the race is more important than the scientific.
The ethical questions of child medical experimentation can be seen in terms of the future good of many against the possible risk to the few, or the moral duty of medical research to overcome disease threatening children as a group, versus the moral imperative to protect each individual child patient. In the case of orphaned poverty-stricken children with little hope of a satisfying life, perhaps their 'legacy' may well be to provide science with the chance of helping other humans rather than spending their lives (which, chances are, are already condemned to being unrealistically short) in a parasitic mode.
Child medical research in one form or another has led to the virtual elimination in industrialized countries of the leading causes of child mortality and morbidity, including tetanus, pertussis, diphtheria, poliomyelitis and measles. Though not yet sufficiently implemented, a simple and effective treatment has been found for diarrhoea (the main cause of child death in developing countries), and progress is being made in treating certain forms of cancer, which is among the largest child killers in the industrialized world.