Ethical and regulatory aspects of embryonic stem cell research.

Ethical issues concerning human embryonic stem cell (hESC) research are reviewed three years after the controversy became a public and political issue in the US and two years after the last article on this topic, which also covered the religious aspects. There are still no consistent regulations worldwide on the regulation of research on hESCs, and debate is still ongoing in some countries. New developments require a reassessment of the situation. In the US, the debate is politically driven. Regulations still vary from one country to another and there are no universally uniform ethical and regulatory standards for hESC research. At present, the most liberal and favourable environments for hESC research are in the UK, Singapore, Sweden, India, Israel and China. In the US, there is no change in the policy of the current government, but developments in the industrial sector and academic institutions, which are not dependent on government funding, are encouraging for future progress. Considerable advances have taken place in hESC research during the past few years to justify a relaxation of restrictions, and suggestions are offered to improve the ethical and regulatory environments for hESC research.