The science, fiction, and reality of embryo cloning.

Although many scientists view cloning as a useful procedure for scientific research into early embryo development -- one that cannot currently be used to produce multiple copies of humans -- the popular literature has led some individuals to view it as sinister. To address the concerns of the public, various conceptions of cloning are distinguished and their basis in fact analyzed. The possible uses, benefits, and detriments of both embryo splitting and nuclear transplantation are explained. Once the nature and purposes of cloning are understood, and the distinctive ethical dilemmas created by embryo splitting and nuclear transplantation are sorted out, these procedures should be clinically implemented to assist in vitro fertilization treatment for those who are infertile and to further other therapeutic and investigational efforts in medicine.