Embryology And In Vitro Fertilization

In vitro fertilization (IVF) is a technique originally developed as a treatment for infertility. In IVF a number of ova are removed from a woman's ovaries and fertilized outside of her body. When they have developed to the eight-cell stage they are transferred back into her uterus, or the uterus of another woman. A number of variations of the IVF technique have been developed, each with its own acronym. These include GIFT (gamete intrafallopian transfer), ZIFT (zygote intrafallopian transfer), ICSI (intracytoplasmatic sperm injection), and SUZI (subzonal sperm injection). As a group these techniques are usually called the ''new reproductive technologies'' or the ''assisted reproductive technologies.''

The development of IVF opened new possibilities for embryological research, and new possibilities for intervention at the embryonic stage of human life. Some of these possibilities are briefly outlined here.

Zygotes can be frozen and stored indefinitely, although 25-50% are lost in the process. Zygotes can be split to form two individuals (cloning), or two or more zygotes can be fused. These two possibilities have not yet been tried in humans. The genetic makeup of the zygote can be determined by preimplantation diagnosis where one cell is removed and the genetic material in this cell amplified through modern gene-amplifying techniques. Genetic engineering can be performed on the zygote.

Ova can be donated from one woman to another, or one woman (a so-called surrogate mother) can bear a child for another couple. Ova from aborted female fetuses can be matured and used in IVF procedures. The normal reproductive span of women can be extended by hormonal treatment and egg donation.

These possibilities can furthermore be combined in various ways and can give rise to quite exotic scenarios. By cloning and embryo freezing a woman could, for instance, give birth to her own identical twin.

It is fairly obvious that some of these possibilities raise ethical questions.

III. WHAT IS THE CONNECTION BETWEEN EMBRYOLOGY AND APPLIED ETHICS?

Embryology is important for applied ethics in three ways: (a) it creates new ethical problems by being the basis of a range of new reproductive techniques, (b) it delivers empirical premises which are part of many of the arguments in biomedical ethics concerning the old problem of abortion and the new problems concerning the reproductive techniques, and (c) the early developments of the fertilized egg have proved a fertile field of examples for developing and testing more general theories of personhood and individuation.

Confusion may be created in the mind of the reader of articles of embryology and ethics if the authors do not make it clear whether they are trying to ''solve'' the ethical problem at hand or to develop a new ethical theory. The reader looking for answers to real world ethical problems is not always satisfied with philosophical analysis performed purely for the sake of its intrinsic philosophical interest.

A. The Moral Status of the Embryo

The moral status of the human embryo and fetus is not a new subject in philosophy. It has a history going back to Aristotle who wrote about the development of the human fetus and identified three consecutive ensoul-ments with a vegetative, an animal, and a rational soul. In scholastic philosophy in the middle ages this idea was further developed in connection with discussions of the proper punishment for abortion, and some scholastic philosophers maintained that male fetuses were finally ensouled with a rational soul 40 days after conception whereas female fetuses were similarly ensouled 80 days after conception.

In modern applied philosophy the question of the moral status of the embryo again emerged in the early 1970s in connection with discussions about the morality of abortion, and the question has continued to be prominent in discussions about ethical problems in the new reproductive techniques. Knowledge about embryology has been used extensively in these discussions. The question has often been stated in terms of whether or not embryos are persons, where a person is taken to be an entity with the moral status of a normal adult human being, including rights not to be harmed and not to be killed.

It is possible to discern two basic positions on the moral status of the human embryo: (1)The human embryo has no intrinsic moral status, but its status depends on the value conferred on it by others (e.g., its mother). (2) The human embryo has intrinsic moral status, independent of how others value it. The third possible position, that embryos begin with very little or no moral status and then gradually acquire more and more moral status as they develop, is probably the common sense view. This gradualist view has, however, been rejected by most ethicists as unsustainable. This may in part be because it shares the problem of many gradualist theories—it is often easier to argue for the extreme positions than for the middle ground. The gradualists will be attacked from both sides and will be vulnerable to the claim that their distinctions are arbitrary. Some versions of the argument from potential do support gradualist conclusions (see the last part of Section III.A.2).

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