New Catholic Times

"Thou it was who didst fashion my inmost parts;
Thou didst knit me together in my mother's womb.
I will praise thee for thou dost fill me with awe!
Wonderful thou art, and wonderful thy works!"
Psalm 139: 13-14, The New English Bible

While human reproduction used to be hidden and mysterious, since the advent of in vitro fertilization physicians and scientists have experienced this wonderful development of an embryo and fetus with their own eyes! They are still filled with awe and wonder. They have been developing new scientific terms to deal with the reality and new moral problems and questions have accompanied their growing skill. They are looking for moral guidance as two "goods" open up to their skill: the wonder to healthy birth and the hope of curing previously incurable debilitating diseases.

There has been considerable discussion about embryonic stem cell research in the media, and many heated opinions have been expressed. However, neither embryonic nor adult stem cell research is totally good or totally bad from an ethical point of view. It is possible to take an embryonic stem cell and still allow the embryo to develop normally, and it is also possible to use unethical means for developing adult stem cells. In other words, this issue is not a clear choice but needs to be nuanced.  This paper will attempt to clarify the biology and research currently in practice in the hopes of lending clarity to the moral issues. It will not discuss the ethical underpinnings of the moral judgments which might be developed for oneself or recommended to others. 

THE HUMAN OOCYTE AND SPERM:

Humans have 22 paired chromosomes plus one pair of sex chromosomes. Females have 22 paired chromosomes plus paired X chromosomes, one of which comes from their mother and the other from their father. Males have 22 paired chromosomes and an XY pair, the X chromosome comes from their mother and the Y chromosome comes from their father. An oocyte (or egg) contains one of each of the paired chromosomes, while the sperm contains one of each paired chromosome plus either an X (which will produce a girl child) or a Y (which will produce a boy child).

The egg or sperm alone will not produce a child. Fertility clinics store eggs and sperm at low temperatures to suspend growth so that they can be used in the future if the donors agree. These may be discarded when they die, are no longer "healthy" (i.e. they exhibit chromosome damage), or the donors request it because they no longer wish to use them and choose not to donate them. Currently in many countries a donor can agree that the unused eggs be used for experimentation.

The egg and sperm can be joined through normal sexual action or in a laboratory, producing a fertilized egg capable of some limited growth. The fertilized egg contains a full number of chromosomes: 46 (22 matched pairs and another set either XX - female or XY - male).  Estimates of the number of genes contained on these 46 chromosomes range between 25,000 and 100,000. The genes contain the "blue print" for development of the child. 

Females begin to develop their primary germ cells (which will later become ova or eggs) around day 21 after implantation of the fertilized egg of their mother. These germ cells produce more than two million primary oocytes (the precursor cells of ova or eggs). However, by puberty the number of oocytes is reduced to 10,000 to 30,000 primary oocytes. A female carries from birth all of the primary oocytes she will ever have. Shortly before a post-puberty female has her menstrual period, one of the primary oocytes will divide into two cells each containing one of the 23 chromosome pairs (it may be the chromosome from her mother or from her father in any random mixture). One of these two haploid eggs (having half of the chromosome material) dies and is absorbed into the woman's body and excreted. The surviving oocyte becomes the developed ovum or egg ready for fertilization. About 400 to 500 such eggs develop over the lifetime of the female, about 12 per year between puberty and menopause. Most are never used to produce a child. In fertility clinics women are given hormones to induce ovulation so that they will produce more than the normal number of eggs in a month. Each mature egg is surrounded by a strong membrane of glycoproteins called the zona pellucida, which a successful sperm must manage to penetrate.

The primary germ cells of the male begin to form on the 21st day of embryogenesis (after implantation of the fertilized egg of the mother). Development of spermatagonia (precursor of sperm) begins with puberty, 13 to 16 years. These enlarge to form the primary spermatocytes which then produce the secondary spermatocytes after undergoing a reduction to haploid state (one of each chromosome pair, i.e. having exactly 23 chromosomes, from either his mother of father, in random selection). Unlike in the female, both secondary spermatocytes survive, and each produces four identical spermatids which develop into sperms. The male continues to produce secondary spermatocytes for his entire life. The process of generating sperms takes two to three weeks, so there is a constant supply of fresh sperm. The total sperm population in a male is itself replaced about every three months.

FERTILIZATION:

In normal reproduction, between 300 and 500 million sperms are injected into the female vagina. They must travel up to the ovum (egg) and still have enough energy to penetrate the zona pellucida (membrane) of the egg and merge with its nucleus. If two sperms penetrate the same egg it dies during embryonic development or shortly after birth. The egg must be ready to receive the sperm which is why the female is open to reproduction only for a few days each month after puberty and prior to menopause. This process is called fertilization. Sexual acts when the woman has not developed an ovum ready for fertilization, or after menopause, are not "open" to reproduction.    

With in vitro (in a laboratory dish) fertilization the penetration is very deliberately carried out. The practitioner selects a "lively" sperm which seems to be healthy and implants it in a developed egg.  

A fertilized ovum or egg is called a zygote.  It is now a single cell with a full compliment of chromosomes, 22 matched pairs and either an XX-female or XY-male combination already determined). During 5 to 7 days after fertilization the zygote undergoes cleavage to form two identical cells, these produce four identical cells and the four produce eight identical cells. After the eight cell stage, they undergo what is called compaction, where the cells bind tightly together forming a compact sphere of sixteen cells called the morula.  Then the outermost cells secrete water into the morula, and as the number of cells increases to between 40 and 150 they form a central fluid-filled cavity called a blastocyst. The zona pellucida (original membrane of the ovum) degenerates, allowing the blastocyst to grow and increase its volume. This state exists until implantation in the maternal uterus. The zona pellucida ultimately disappears completely, allowing the blastocyst to invade the endometrium of the mother's uterus, performing implantation.

Prior to implantation, the cells are called totipotent, that is, they have the potential to form all of the different cell types in the developing embryo and also the placenta, amniotic sac and other needed embryonic support tissues. All of the cells contain the same genetic material. At this stage, some cells can be removed and the remaining cells will compensate for their absence, and develop a normal embryo, fetus and baby.

For in vitro fertilization, these cells are frequently removed by biopsy and examined and subjected to genetic diagnosis to determine whether or not there is a known genetic disorder which would indicate that they should not be transferred to the mother's uterus.

CONCEPTION:

When the morula is ready for implantation in the mother's womb, it form two layers of cells, and is called a blastocyst.  In the blastocyst stage, the inner cell layer (that will soon differentiate into the embryo and its membranes) consists of pluripotent cells, also called embryonic stem cells.  The embryo plus its membranes is called the conceptus and the process of implantation is called conception. It is the pluripotent embryonic cells which are sought in most experimental research projects. 

On August 9, 2001, President George W. Bush limited U.S. federal research funding for embryonic stem cell research to four already existing cell lines. However, these existing cell lines will never be suitable for use in humans, since they have all been "fed" animal broth and tissue to keep them alive. There is a high probability that a graft from these cell lines would be rejected by the recipient [Nature Medicine published a study of this issue on line, January 24, 2005].

In in vitro fertilization, a number of fertilized eggs are cultured in preparation for the implantation of the blastocyst in a potential mother. There is about a two week "window" between the formation of the blastocyst and the change of pluripotent cells to the multipotent cells which form the three layers of the human baby's body. 

In the normal pregnancy sometimes the blastocyst fails to implant itself and form the placenta, in which case the pregnancy is lost. Often the woman does not know that an egg was fertilized. Some contraceptives are aimed at this stage of embryogenesis, before the conceptus is formed, by preventing the implantation and conception. For laboratory fertilization, this short window must coincide with a woman's ability to accept the blastocyst and help it to form a placenta so that it can grow further. This is medically induced by artificially infusing hormones to help implantation in the woman. Only four (or less) blastocysts may be inserted in a woman's ovary at most clinics. Usually only one or two make it through implantation and formation of a placenta. The other blastocysts die and are excreted.  Sometimes in vitro fertilization results in unwanted multiple births.

If two blastocysts become implanted either through normal fertilization of two ova or through in vitro fertilization, fraternal twins are formed. If the embryonic stem cells become disconnected or disassociated, identical twins may form. There are many possible combinations, however these are all unusual.

The Blastocyst:

i The blastocyst is the source of embryonic stem cells for research purposes. Taking these cells may destroy the blastocyst and interfere with the normal development of the embryo. However, it is possible, according to very recent experimentation, to remove a small number of these embryonic stem cells and have the remaining cells compensate and  go on to form a normal embryo. This has been successfully done in the mouse embryos but not yet (to my knowledge) in human embryos.

Tissues and organs produced through embryonic stem cell research cannot be transplanted into humans without causing immune rejection problems, since the DNA is different from the patient's DNA. Mouse fibroblasts have been used to "feed" human embryonic stem cells in the past, but this practice is being phased out and only human or "neutral" (non-animal) food is being used so as to prevent rejection if or when the tissue is implanted in a human being [Lancet Medical Journal 8 Mar. 2005]. 

However, even when only "neutral" or non-animal food is used, the same precautions which are used for blood transfusions must be used with any tissue transplant. Therefore embryonic stem cell research is primarily for the development of physician's skills, and poses a number of transplant rejection problems for patients.  Some researchers dream of tissue banks similar to blood banks, but this appears to be unachievable at this time.

Embryonic stem cell research has produced ethical discussions, heated opinions and stress in the research community. In a speech in March 2009, President Barack Obama removed the 2001 government prohibition against new embryonic stem cell lines imposed by George W. Bush.  However, embryonic stem cell research is still subjected to the regulations of the Department of Health and Human Services, and human experimentation ethics committee approvals at the hospital or University proposing any experimental protocol. Hopefully removing governmental interference with research will lead to more open proposals, guidelines, safeguards, and ethical discussions.  [See: http://stemcells.nih.gov/policy/2009draft.htm  for the draft 2009 guidelines available for review, from Health and Human Services]

Under the Omnibus Appropriations Act for FY2009, embryonic research remains prohibited, under the Dickey Amendment, for (1) the creation of a human embryo for research purposes; or (2) research in which a human embryo or embryos are destroyed, discarded, or knowingly subjected to risk of injury or death greater than that allowed for research on fetuses in utero. This amendment does not prohibit removing some embryonic stem cells from the pre-implantation blastocyst. The 2009 Draft Guidelines for embryonic stem cell research would allow funding for research using human embryonic stem cells that were derived from a blastocyst, created by in vitro fertilization (IVF) for reproductive purposes, that was no longer needed for that purpose. Doner consent would be required and the blastocyst could not be implanted and further developed into a conceptus. Also prohibited would be extraction of the germ cells of a conceptus for research purposes.

Austria, Denmark, France, Germany, and Ireland do not allow the production of new embryonic stem cell lines, but the creation of embryonic stem cell lines is permitted in Finland, Greece, the Netherlands, Sweden, and the United Kingdom. 

In an Editorial by Fiorentino in the Vatican's L'Osservatore Romano, published 7 May 2009, it was suggested that U.S. President Barack Obama's positions on abortion and other life issues "have not confirmed fears of radical changes".  This provides some confirmation that there is a difference in tone between the Vatican and the most ardently pro-life circles in the American Catholic church, including a growing number of American bishops. In general, several voices in the Vatican have taken a moderate and conciliatory line on the Obama administration, while several U.S. bishops, buoyed by a network of pro-life activists, have been more pugnacious. Fiorentino argued that Obama's controversial executive order on embryonic stem cell research was actually fairly restrained, because it still prevents the creation of embryos for purposes of research or cloning, and it limits the use of federal funding for research to "surplus" embryos. Fiorentino also argued that Obama's support for the "Pregnant Women Support Act" represents a "rebalancing" of his abortion policies "in support of maternity."

Sr Rosalie Bertell a Grey Nun of the Sacred Heart was president of International Institute of Concern for Public Health from 1987 to 2001. She founded the International Medical Commission Chernobyl in 1996. She received the Hans-Adalbert Schweigart price from the World Union for Protection of Life. As well She is the recipient of five honourary degrees. Among her many awards can be numbered the Alternative Nobel Prize, Right Livelihood Award; World Federalist Peace Award; Ontario Premier's Council on Health, Health Innovator Award; the United Nations Environment Programme Global 500 award and the Sean MacBride International Peace Prize.