Questions of human reproduction inevitably define what it means to be human, and the moral issues which arise in connection with sex and reproduction are among the most divisive controversies of our time. The development of "test tube baby" technologies presents us with moral issues which demand answers, and require our most careful thought and reflection.

The German theologian Helmut Thielicke once argued that we learn more about ourselves and our most fundamental convictions by considering those "borderline" questions which resist easy answers. This is certainly true in the case of the new reproductive technologies. One of these "borderline" questions is raised by the development and spread of in vitro fertilization techniques, known as IVF. This issue cannot be understood apart from the foundational issues of human dignity, the meaning of personhood, and the integrity of marriage and the family.

The reproductive revolution is upon us. The past half-century has seen the development of reproductive technologies previous generations could not even imagine, much less consider in moral perspective. These technologies have radically expanded human control over the biological process, and have been designed both to prevent and to achieve successful pregnancy. Some legal theorists now argue for a new human right--the right to complete "procreative liberty," ensuring an individual's right to these new technologies.

The technological basics of in vitro fertilization technologies are easy to understand. The moral issues are far more complex. In vitro literally means "in glass," for the actual fertilization of the egg takes place in a laboratory context [early on, in a petri dish], rather than in the woman's reproductive system. While infants conceived by this method are often called "test tube babies," this is a misnomer, as no test tube is generally used. The phrase does, however, underline the technological character of the conception, which takes place in the laboratory.

The moral issues are more complex. What does it mean to separate conception from the act of sexual union? To whom should these technologies be made available? What is the moral status of the fertilized embryos? Those who dismiss these questions as irrelevant or inconsequential show disrespect for human dignity and human life.

At one level, the moral and theological issues at stake in IVF are identical to those related to artificial insemination. The insemination may be done with sperm from the husband in a married couple (homologous insemination) or with sperm from a donor (heterologous insemination). Beyond this, a new set of issues emerges. In IVF, an egg is removed from a woman, and is fertilized in a laboratory setting by the insertion of sperm cells into the dish. Once the egg is fertilized and the exchange of chromosomal material takes place, the embryo is implanted in the uterus, with the hope that implantation will occur and a pregnancy will continue to healthy birth.