I found this @ torah.org:
http://www.torah.org/features/secondlook/stemcell.html"
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JEWISH LEGAL CONSIDERATIONSWe begin the outline of the Jewish legal approach to stem cell research by stressing some general overarching principles. In contrast with other religions, Judaism has no problem with "playing G-d," provided we do so according to His rules as expressed by authentic Jewish legal mandate. Far from being shunned, "playing G-d" in the Jewish tradition is, in fact, a religious imperative: the concept of emulating G-d is implicit in the mandate to heal and provide effective medical relief wherever possible. Of note, the only two "professions" ascribed to G-d Himself are those of teaching and healing. By teaching and/or healing, we fulfill the obligation to "play G-d." There's no reason that microscopic manipulation of a faulty genetic blueprint should be any different than surgical manipulation of a defective macroscope -- that is, visible to the unaided eye -- tissue or organ. Normative Jewish law sanctions -- nay, encourages -- medical intervention to correct both congenital and acquired defects, and makes no distinction between stem and somatic (body) cell tissues.
The crucial distinction here is between the permissible act of correcting a defect and the forbidden act of attempting to improve on G-d's creations (generally proscribed by the laws of cross-breeding). For example, it would be permitted, were it possible, to correct the genetic defect which leads to Down's syndrome, but manipulating genes to produce a "perfect-bodied" six-footer with blue eyes would be prohibited.
There would, therefore, be no Jewish legal problem with using stem cells derived from adult tissue. Similarly, it would appear that using cells from umbilical cord tissue would be permissible. A rather minor concern here might be the following: May one have umbilical tissue collected and frozen so that the cells will be available in case one requires stem cell therapy sometime in the future? Is this degree of effort, in trying to ensure one's health, appropriate or excessive?
While there are few Jewish legal objections to deriving the stem cells from adult or umbilical cord tissue, the problems arise, however, with deriving stem cells from the embryonic tissue.
Post-implantation embryonic tissue (that is an embryo already implanted into the uterine wall) is after all, an early fetus; clearly no sanction would be given to aborting a fetus in order to obtain stem cell tissue. Even were fetal tissue necessary to provide life-sustaining therapy for a patient, no sanction would be given to sacrifice an innocent fetus even in the interest of saving another life. The only exception to this rule is the obligation to forfeit the life of the "non-innocent" fetus when its continued existence constitutes a danger to its mother by virtue of the fetus's pursuer ("rodef") status.
Even fetal life before the 40th day of gestation -- which is considered "mere water" -- could not be aborted in order to obtain stem cell tissue. Prior to 40 days, a miscarried fetus does not trigger birth-related purity issues, and therefore is of lesser status than a more mature fetus. (There is a large body of rabbinical writings regarding the 40-day status of a fetus.)...
TOWARD THE FUTURE
The prime source of embryonic stem cell tissue is embryos that have not been implanted into the uterine wall. As discussed above, they are usually the "by-products," spare embryos left aside during in vitro fertilization in order not to dangerously overload the mother's uterus. The Jewish legal status of these spare, non-implanted embryos is somewhat unclear. Some rabbinical opinions suggest that in addition to the 40-day milestone, an embryo doesn't reach fetal status until it is implanted into the uterus. Prior to that, while still in a petri dish, or other artificial medium, it cannot develop into a viable fetus. Therefore such early embryos have no real life potential at all and they're not considered alive. Consequently, there would be no Jewish legal opposition to disposing of them, researching on them, or deriving stem cell tissue from them.
The status of pre-implantation embryos has another potentially important Jewish legal consequence. Pre-implantation genetic diagnosis (PGD) offers a promising approach to prevent the birth of genetically defective children. By studying embryos before implantation into the uterus, it is possible to identify those defective genes. By selecting only genetically intact embryos for implantation, the development of genetically defective fetuses would be avoided. Assuming the pre-implanted embryo has not reached the level of a fetus, Jewish legal sanction may be possible.
The ethical issues raised by stem cell research and therapy are, of course, not only of interest to Jews. In an unprecedented national broadcast, President Bush defined some fairly restrictive regulations. Just recently the administration argued strongly in favor of banning all research into human cloning. Evidently the crossroads of medical science and the generation of life itself raises fears and genuine concern in the minds of many thinking people.
It appears that Jewish legal concerns may be more permissive than is generally understood. Clearly, it behooves us, as Jews, to avail ourselves of whatever Torah and scientific knowledge we can -- not only as we try to find the Jewish legal guidance for ourselves, but perhaps equally importantly -- as we strive to fulfill our national mandate to be a Light Unto the Nations -- to help shed light on these vexing issues for society at large.
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