A scientist's view of the ethics of human embryonic stem cell research

Scientists are rarely immoral and seldom even amoral. The ethical principles that underlie much of their own work are shared with scientists in other countries to a much greater degree than the cultural and religious differences among those countries would lead one to expect. Like me, few will have had any formal training in bioethics; so how might life scientists approach the varied ethical issues that arise in human embryo and stem cell research?