LOS ANGELES: Short of sending an anthrax-filled letter, the best way to rattle Congress is to announce a breakthrough in human cloning. The latest example is the carefully orchestrated claim by a small Massachusetts biotech company to have “set the stage” for “a potentially limitless source of cells for transplantation” by creating three four- to six-celled cloned human embryos.

President Bush and several senators have called for immediate passage of a bill that the House approved last summer that would prohibit any creation of human embryos through cloning. Yet to fill the void caused by scientists’ lack of self-restraint, lawmakers still must bridge the right-to-life versus right-to-choice chasm into which past attempts to control human cloning have fallen.

Most serious scientists doubt that any would-be cloners can bring a human replicant into the world any time soon because the process of resetting the biological clock through cloning is fraught with problems. Random and as yet poorly understood genetic problems occur when an embryo gets its start through cloning rather than sexual fertilization.

Even if newer methods reduce the gross developmental problems that have been found in many cloned animals, it still takes hundreds of attempts to get a handful of animals that survive beyond the newborn period. This level of fetal waste and risk of harm would make any attempt to produce a human clone the worst sort of reckless, unethical experimentation.

It is easy to see why abortion opponents would want to ban not only reproductive cloning but also cloning embryos for laboratory research; both treat human embryos as objects. If the federal government only forbade reproductive cloning, it would be implying that scientists could make cloned embryos as long as they promised to destroy them. For conservatives, that is unacceptable.

Many liberals have taken this as their signal to defend research cloning, even if they agree that reproductive cloning is a bad idea. Besides not wanting to give any support to those who oppose embryo research, the liberals worry that limiting research on human cloning will deprive patients with diabetes, Parkinson’s and other diseases of made-to-order tissue and organ transplants.

Yet this is a false impression, fed by Advanced Cell Technology, the Massachusetts company, and others who misleadingly call their research “therapeutic cloning.” In fact, years of basic research - which can be done with stem cells derived from embryos discarded by fertility clinics - will be needed before any therapy using cells cloned from a patient could even be tried. Alarm over the prospect of reproductive cloning has made ACT’s latest results seem more significant than they are. The researchers failed to show that they could produce stem cells or that the cloned embryos were free of genetic defects.

Nonetheless, even if the latest report is significant mainly for ACT’s financial prospects, it is a reminder that once scientists manage to produce normal human embryos through cloning, achieving a pregnancy will be comparatively easy. Veiled by the privacy of the physician-patient relationship, how could it be prevented?

Thus an effective ban on reproductive cloning will require halting work on the creation of cloned embryos for other purposes. If Senate Democrats are worried that a permanent ban would go too far, they ought to amend the House bill to turn the flat ban into a five- or 10-year moratorium. This would allow further knowledge to be accumulated about mammalian cloning as well as serious, sustained reflection about the sort of world that human cloning could engender.

This middle road should appeal to all groups, including those that oppose all embryo research and those that accept such research but think reproductive cloning is a bad idea that will slide into the creation of classes of clones genetically modified to be the overlords and underlings of the future.

Also, a moratorium should reassure researchers and patient advocates that if it becomes apparent that laboratory cloning is essential to achieving important therapeutic goals, that door has not been forever closed. With more knowledge of the science and better understanding of the risks, a controlled therapeutic programme might be devised with safeguards against misuse of cloning in surreptitious reproductive efforts. In the meantime, halting further movement toward human cloning can be common ground for people who differ on other issues. —Dawn/LAT-WP News Service (c) Los Angeles Times./