Knowledge about human reproductive biology is rapidly expanding, and many applications of reproductive technologies are possible. There are two main kinds of ongoing embryological research, in vitro research and research on implanted fetuses. Both need to clarify one significant ethical distinction: the situation when the embryo is planned to be born, or to perish. Ethical issues of reproductive technologies must be examined both from the prospective of the benefits gained by some individuals, and the possibility of undesirable social consequences. For example, a personal benefit in which only male children would be desirable could result in a skewed sex distribution in the population.

Embryo stem cells are considered a new hope for a source of supply for transplantation of internal organs and genome project studies, but such a technology implies discontinuation of possible life, since the conceptus (embryo and/or...