Debate over how far man should go in manipulating human life in the laboratory is mounting. The growing use of ''test tube baby'' techniques and the emergence of other reproductive tools is raising a host of complex legal, social, and ethical questions that touch on the already emotional issues of life and death and parenthood.
The issues have become particularly focused within the past week because of the uncertainty surrounding the fate of two frozen embryos in Australia. But other recent events have surfaced that also underscore the challenges posed by the new technologies.
In Britain, for example, an advisory committee has just completed an 18-month study looking at the implications of the whole artificial-reproduction area. The committee will be recommending legislation on everything from commercial surrogate motherhood agencies, those that charge fees to arrange for one woman to bear a child for another (it suggests a ban), to research into human embryos (it suggests controls) to the freezing of embryos (it approves of the idea).
In Australia, meanwhile, even before the frozen-embryo case arose, a row had broken out over the future of test-tube baby research. In May, Dr. Robyn Rowland , a leading figure in the field, resigned from a committee overseeing a research team in Melbourne in protest over where the research was headed. She called for a watchdog agency to monitor the test-tube baby and genetic engineering area.
But it has been the case of the two ''orphaned'' embryos and the question of whether they could inherit a wealthy estate that has riveted most of the attention. In many ways the questions it raises go to the heart of the issues behind in vitro fertilization (the process of fertilizing a human egg in a laboratory dish).
In 1981 a Los Angeles couple, Mario and Elsa Rios, enrolled in a test-tube baby program in Melbourne after their young daughter had died. Several eggs were removed from Mrs. Rios and then fertilized in the laboratory. One was implanted, but she later had a miscarriage. The two other embryos were frozen for possible future use.
Last year the couple died in a plane crash, leaving the question of whether the embryos might be able to inherit the Rioses' estate (estimated at more than practical standpoint, that may never occur. For one thing, it is considered unlikely the embryos would survive thawing. They were frozen at a time when the technique was not well developed. Since then, using new methods, one baby has been delivered in Australia from an embryo that had been frozen. (Attempts have been made in the United States, but none have been successful.)
For another thing, lawyers handling the Rios estate contend that the sperm used to fertilize the eggs in the laboratory came not from Mr. Rios but from an anonymous donor. Thus, since he isn't a biological parent, any potential claims to the estate by a child resulting from the embryos would be groundless.
Whatever the specific contentions, there are other issues likely to come up as reproductive technologies continue to outpace laws and attitudes. For instance:
* Do embryos formed outside the womb have any legal rights?
* Should embryos be given some form of protection? Should, for instance, the use of fetal tissue in experiments be prohibited?
* What happens to the frozen embryos of parents who die or are divorced? Should they be destroyed, donated to another childless couple, or kept frozen?
* How long should they be allowed to be kept frozen? The technique was devised as a convenient storage tool; unused fertilized eggs could be kept frozen for future use should a pregnancy fail. But the technique could end up affecting such things as family planning: In theory, a couple could decide to produce embryos early in their marriage but space out when their children would be born.
Underlying the complications - and debate - is that embryo freezing is another reproductive tool that allows a ''third party'' to join the traditional marriage relationship. It is already possible, using such means of conception as in vitro fertilization outside the womb, surrogate motherhood, and the transfer of an embryo from one woman to another (this was done successfully for the first time earlier this year), for several ''parents'' to get involved in the reproduction process. These might include an egg donor, a sperm donor, a woman who provides her womb for part of a pregnancy, as well as the couple that raises the child. Embryo freezing doesn't necessarily add to the combinations. But, as a new storage medium, it can make some easier to do, and it raises a few new possibilities.
Given the political sensitivities involved, regulations in the whole area have been scarce. In the US, some two dozen states have laws addressing artificial insemination by donor. But almost none deal with surrogate motherhood , test-tube children, or frozen embryos. ''At the present time we have a dearth of policies to cope with these things,'' says Clifford Grobstein, a biology and public policy professor at the University of California, San Diego.
In Britain, the new report by the Warnock Committee deals with many of the issues. Its full findings, to be published later this summer, are bound to be a hot item on the country's social agenda. In Australia, a government-appointed committee in Victoria State is looking into the ethics of test-tube births and is expected to report in July. Included on its list are the two frozen embryos.
Some observers believe it is now time for a group to be set up in the United States to examine the area, an idea that has been suggested before. ''Do we want to have some public policy on defining mothers and fathers, or do we want to let private contract decide,'' asks George Annas, a professor of law and medicine at Boston University.
Whether that comes about or not, issues are bound to keep surfacing. New technologies loom on the horizon. Plenty of people want to use ariticial means of conception to have children (as many as 1 in every 6 American couples have fertility problems).
''In one sense, the capacity of the technology has simply outstripped society's ability and willingness to examine the ethical and legal ramifications of all this,'' says Arthur Caplan, associate at the Hastings Center, a New York research institute dealing with ethical problems in health care. ''As with other medical therapies, we are seeing more of a technological imperative. Because we can do things, we do them.''