MAKING BABIES; The New Science and Ethics of Conception.By Peter Singer and Deane Wells. Scribner's. 245 pp. $14.95; THE MOTHER MACHINE; Reproductive Technologies From Artificial Insemination To Artificial Wombs By Gena Corea. Harper & Row. 374 pp. $18.95.

WHEN BRITISH physicians announced in 1978 the birth of the first "test tube" baby, Louise Brown, they also alerted the world to the birth of a new industry -- the manufacture of human embryos. To be sure, the raw materials, eggs and sperm, came from natural sources, much as they do in the production of yeast or genetically engineered insulin. But the embryo itself was artificial, produced in laboratory glassware by human manipulation, then implanted in a woman's womb.

Since Louise Brown's birth, close to 1,000 babies have been born using this tecnology in Britain, Australia and the United States. Now embryos can be not only manufactured but also frozen, shipped from place to place, and transferred from woman to woman. Soon embryos will be sex typed, allowing parents to select the desired gender. Also soon, they will be "twinned," or divided into pieces, each of which can grow into a separate, identical embryo, or clone. Somewhat later it will be possible to alter the genes of embryos while they are in the laboratory dish, allowing scientists to correct for inherited defects. Eventually, embryos will be kept alive in the laboratory longer and longer, and premature babies saved earlier and earlier, until the techniques are in place to sustain babies for the full nine months in artificial wombs. Even sooner, embryos will be grown long enough in the laboratory that their organs could become spare parts for organ transplants.

Yet, except within conservative religious groups, response to this new biotechnology has been curiously halfhearted. As with past technologies, like nuclear power and chemical pesticides, the public has seemed quite willing to embrace the benefits -- in this case, hope for the infertile and the infirm -- and to worry about the costs later. In the United States and abroad, government regulation has been spotty, sometimes imposing curbs on government funded research, but generally leaving private development largely unsupervised.

Experts almost unanimously find this approach far too casual. Typical of the voices of caution are Peter Singer, a philosopher at Monash University in Australia, and Deane Wells, a member of the Australian parliament, authors of Making Babies: The New Science and Ethics of Conception, originally published last year in England. Sketching scenarios including routine in vitro ("test tube") fertilization, surrogate mothers, sex selection, genetic engineering, cloning and embryonic spare parts, Singer and Wells ask that each stage of developmnt be carefully evaluated before proceeding to the next, and that basic ethical and environmental standards be set.

The restrictions that Singer and Wells would place on reproduction technologies are relatively few and remarkably lenient, however. Embryos could be harvested for spare organs until the embryos were old enough to be sentient, and cloning would be permitted if limited, say, to "one replica per person."

With modest precautions, Singer and Wells foresee reproductive technology overcoming many of the miseries created by random evolution and human society. Abortion could be replaced, they suggest, by a process of transferring a live fetus from the reluctant mother to a willing one. Artificial wombs, or ectogenesis, could be the final, necessary step in women's liberation.

FAR MORE CAUTIOUS is writer and feminist Gena Corea, author of The Mother Machine: Reproductive Technologies from Artificial Insemination to ArtificiaWombs. Corea sees greater potential for abuse of the new technology, partly because she sees more abuse occurring already. While Singer and Wells concern themselves largely with risks to fetuses, Corea shifts the focus to the women who bear them. In Corea's view, society has thus far protected fetuses from the dangers of reproductive technology considerably better than their mothers.

According to Corea, only about 15 percent of the women who seek in vitro fertilization actually have successful births. And many are not adequately informed of the risks, including the odds of becoming pregnant. Louise Brown's mother Lesley did not clearly understand that hers was the first "test tube" pregnancy until shortly before Louise was born. She assumed that earlier test tube parents had kept discreetly quiet. So did Judith Carr, mother of the first American test tube baby born in 1981. For the Browns, the financial burden of IVF experimentation was so great that they cut corners, once leaving the hospital a day early after surgery to recover eggs. Lesley's wound began bleeding on the train home. After a trip in which Lesley's husband carried her through four transfers, they arrived home exhausted, soaked with blood and in tears. According to Corea, women for at least six years had submitted to such grueling rounds of surgery, hormonal treatments and anxiety, in hopes of becoming pregnant, and the physicians involved did not really understand why in Lesley Brown's case the embryo finally took.

Such abuses are part of a pattern that Corea sees extending dangerously into our technological future. From primitive times, she argues, men have sought to control and emulate women's ability to bear children and to ease their alienation from the birth process. In the last century, a largely male obstetrical profession has intervened more and more, bringing men closer to the birth process and distancing women from it.

Corea predicts that in vitro fertilization (IVF), now an option for the infertile, will be applied to more and more women to overcome more and more minor problems. As with earlier obstetrical interventions like bottle feeding, fetal monitors and Caesarian sections, IVF will be promoted as safer than the natural way. Also analogously, this new technology will be used to compensate for the problems of previous technologies, as it now compensates for fertility problems created by IUDs and DES. Ultimately, Corea sees the new reproductive technologies giving men the power and the inclination to reduce women to the status of domestic animals. The book is, as she describes it elsewhere, "a scream of warning to other women."

Corea is undoubtedly right that decision- making about this incredible new technology has rested with a small elite group of physicians -- she calls them "pharmacrats." She cites ample evidence that these doctors have at times been careless, ambitious, shortsighted and negligent. They have indeed referred to women as "clinical material" and "oocyte (egg) donors." It weakens Corea's argument, however, to regard women as the sole victims. On this issue, society cannot afford such divisiveness. Fundamental decisions about the future of human life are taking place haphazardly, and both women and men need to regain control.

Despite their differences, the authors of both books recommend essentially the same solution: more government intervention. Singer and Wells propose a national bioethics commission that would make recommendations to the national government. They concede that the record of the erstwhile U.S. Department of Health, Education, and Welfare Ethics Advisory Board was "scarcely an encouraging example," because its recommendations were confusing and largely ignored. But they believe that a body that is more expert and less representative will be more effective. Corea prefers a regulatory body like the U.S. Environmental Protection Agency to oversee the new reproductive "medibusiness" that markets the new reproductive technologies.

In any case, both books urge immediate public discussion and debate. "Each time we do it, we will get better at it," says Corea. But, add Singer and Wells, "We will need to learn fast."