On Tuesday the US House of Representatives passed a bill that would ban the cloning of human embryos and thus curtail certain forms of stem cell research. The two of us, a women's health activist and a prochoice biologist, provided testimony before a congressional committee last month in favor of this bill.

Why would political progressives and defenders of reproductive autonomy advocate restricting what some have characterized as an area of medicine with great promise, thus finding ourselves on the same side of the issue as antichoice conservatives? We believe that any benefits that may result from stem cell research that utilizes ''clonal embryos,'' that is, genetic duplicates of existing individuals, would be far outweighed by the threats to women's health and to our sense of our humanity posed by creation of such embryos.

Because clonal human embryos could be used for experimental purposes and ultimately as sources of donor-matched embryo stem cells, some researchers and biotechnology companies have been resisting any restrictions on their ability to produce them.

Recently, Advanced Cell Technology in Worcester announced that it has already movged forward with producing clonal embryos using methods similar to those used to clone Dolly the sheep. However, many scientists and physicians oppose bringing clonal embryos to term. Their primary basis for this opposition are the hazards that have led to fetal and postnatal deaths, birth defects, and health problems with advancing age, in the majority of cloned animals to date.

Although these reasons alone are sufficient to halt reproductive cloning experimentation, we believe that social and ethical considerations should still be paramount in creating public policy surrounding clonal technologies, even if research with clonal human embryos and cloned animals bring the technical problems under control.

Supporters of women's health and reproductive rights have been relatively silent on human reproductive cloning (where a clonal human embryo is brought to term) and stem cell research that depends on cloned embryos. However, a recent statement signed by more than 100 prochoice advocates and organizations calls for an effective ban on human reproductive cloning.

Some signatories are concerned primarily with the risks to women's and children's health and do not want women and children subjected to mass experimentation of the sort we are now seeing with cows, sheep, and pigs. Moreover, women whose eggs are harvested for cloning have to be treated with hormones to induce superovulation, possibly putting them at increased risk of ovarian cancer with no benefit to themselves. Other signatories emphasize that cloning would violate deeply and widely held convictions about human individuality and dignity. Any person produced in this fashion would be an experiment, someone designed to possess specific characteristics of a preexisting genetic prototype - not the normal genetic ''roll of the dice'' that has led to each of us being a genetically unprecedented individual.

It will be all but impossible to enforce a ban on the creation of fully formed human clones if clonal embryo research is allowed to proceed. In the current climate, with several ''cowboy'' researchers already moving forward with efforts to bring cloned humans to full term, it is critical that public policies actively thwart such efforts - at least until international agreements that would effectively ban the cloning of genetic duplicate humans are firmly in place. Otherwise some clonal embryos are likely to be implanted in the uteri of women who are willing to be part of such cloning experiments.

And what new assaults on a woman's reproductive rights would follow from her gestating a banned clonal embryo or wanting to terminate a pregnancy involving some company's ''property?'' Advocates of human reproductive cloning and other forms of inheritable genetic modification have attempted to appropriate the language of reproductive rights to support their case. But there is an immense difference between seeking to end an unwanted pregnancy and seeking to create a genetically duplicated or modified human being. It is an unfortunate consequence of the rise of the new genetic technologies that ''reproductive choice'' is increasingly taken to include the right to manipulate the genetic composition of the next generation.

A ban on creating clonal embryos would not foreclose the use of human embryos resulting from in-vitro fertilization procedures for valid medical research, including their use to generate embryonic stem cells. Assertions that clonal embryos will be essential in the development of currently sought medical therapies are premature, and alternative avenues of stem cell research and other approaches to dealing with immune system rejection might well achieve these therapeutic goals without ever utilizing stem cells from clonal embryos.

As the new genetic and reproductive technologies proliferate, the question continually arises as to where to draw the line. Because embryo cloning will compromise women's health, turn their eggs and wombs into commodities, compromise their reproductive autonomy, and, with virtual certainty, lead to the production of ''experimental'' human beings, we are convinced that the line must be drawn here.