"one can justify sacrifice of some embryos"

Here's one argument for limits on science from a Commentary in Stem Cells, "A Proposed Stem Cell Research Policy" by Louis M. Guenin of the Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts, USA :

COMMENTARY
A Proposed Stem Cell Research Policy
Louis M. Guenin

Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts, USA

Correspondence: Louis M. Guenin, Lecturer on Ethics, Department of Microbiology and Molecular Genetics, Harvard Medical School, 200 Longwood Avenue, Boston, Massachusetts 02115, USA. Telephone: 617-484-5591; Fax: 617-738-7664; e-mail: guenin@hms.harvard.edu

The aspirations of scientists and patients for human embryonic stem cell (hESC) research in the U.S. motivate attention to the nitty-gritty of law and regulation and its confluence with such moral consensus as lies within our reach. Federal law and regulation form a tangle. Analysis yields several conclusions not widely appreciated. A legislative enactment is the rate-limiting step of federally funded research, the restriction of research imposed by the previous administration’s policy as reprised in current proposals fails to achieve its objective of avoiding complicity in embryo sacrifice, the current administration’s policy is another failed noncomplicity scheme under which research cannot be expanded without demolishing its putative justification, and the Food and Drug Administration has already effectively interdicted procreative cloning. While it is not plausible to deny complicity in embryo sacrifice when performing or funding hESC research, one can justify sacrifice of some embryos by an argument whose premises are consistent with a wide range of moral and religious views. This paper proposes a rule of public policy providing for the use of donated embryos barred from the womb. This rule would optimize research while manifesting its moral justification. The rule is suitable for implementation by any government that funds hESC research. The rule’s justification provides a cogent argument for such incremental steps toward its implementation as become politically feasible from time to time.

The sacrifice of one human life for another, by organized, intentional and regulated means, much less with government funds, can never be justified when that life is not a threat to another.

How far we have come from the ancient (Greek) affirmation that "First, do no harm."