A brief discussion of how ethics can limit research in various fields.
How do ethics limit research in the natural sciences?
The natural sciences are those concerned with the understanding of natural phenomena, and as such include chemistry, biology, physics, astronomy and geology. Although the ethics of research and scientific misconduct apply to all of these fields (including considerations of plagiarism, fabrication of data, misleading presentation of results and who should be given authorship of publications), it is the sciences that involve living creatures that must give greatest consideration to ethics.
In experiments involving animals, care must be taken to minimise the amount of pain or discomfort caused to the subjects. Scientists are required to set out the ways in which they have minimised the suffering of animal subjects, and to take pains to explain how the use of live animals was directly necessary and of demonstrable value. In a way, this does limit researchers, as it prevents idle experimentation. However, as the experiments prevented by this are definitionally cruel and of little importance, this is probably no great loss.
Geneticists in particular are often restricted by research laws and ethical quandaries. For instance, although genetic manipulation of human embryos is now permitted, none of the products of these practices are allowed to be implanted or carried to term, so the effects of genetic manipulation are unknown beyond the embryo. Human experimentation is also very tightly controlled with regard to ethical issues. The Declaration of Helsinki is the most important document in human research ethics. It includes the imperative that the subjects must always be informed and willing, respected and cared for by the researchers, and that their welfare is always of greater importance than scientific advancement.
Although these are important guides for modern research, it should be noted that the scientific community has occasionally benefitted from deeply unethical studies. For instance, experiments carried out at Dachau and Auschwitz by Nazi scientists still provide almost all modern knowledge on how long it is possible to survive in various temperatures of cold water. Reliance on these studies is unlikely to change, as several hundred people were killed in the process, making them unrepeatable.