DURING the forthcoming parliamentary session legislation will be enacted either to permit or prohibit research which causes the destruction of human embryos. The case for such research rests primarily upon the benefits which, it is claimed, will result; the case against is simply that the product of successful fertilisation of a human ovum by a human sperm is a living member of the human species whose life deserves the protection of law.
The study of embryology has long established that in those species in which sexual reproduction is the norm a new life begins at fertilisation when the sex and unique genetic identity of the embryo is
established. Those who wish to pursue human embryo research do not deny this; instead they erroneously suggest that since specialisation of cell function does not begin for 14 days, the product during that period is not an embryo but a pre-embryo. Curiously this concept has not been applied to the early embryo of any other species. This is not v;,.ce the word pre, no meaning: even the New Scientist, which is not opposed to human embryo research, condemned its use stating (November 21 1985) "Definitions are as important in science as truth. Calling things by other names to suit the arguments will fool no-one." The proposed permissive legislation on human embryo research is based upon the recommendations of the Warnock Committee which, inexcusably, had no human embryologist as a member. Had it done so the events of the first
14 days could not have been ignored. After fertilisation the human embryo is within a protective membrane which disappears about the fifth day. Immediately some of the embryo's cells begin to secrete a hormone without which it would die. These same cells are also invasive allowing the embryo to bury itself within the lining of the womb during the process of implantation which is completed on day 12. In addition primitive skin is formed on day seven and the special cells which line the gut and the respiratory tract appear on day nine. These and many other events, all of which are essential for survival, occur before the 14th day of embryonic life.
A more insidious argument used to justify killing human embryos during research is that the majority of naturally conceived human embryos die before the 14th day. Even if this were true it would be an invalid argument since it is comparable with advancing death from natural causes as a reason for unlawful killing. In fact a Medical Research Council study has shown that less than 10 per cent of naturally conceived human embryos are lost before day 14. Sadly, more than 90 per cent of IVF embryos placed in the womb are lost before this stage.
Since very occasionally one embryo produces two individuals, ie identical twins, it has been suggested that destructive human embryo research during the first 14 days should be permitted because of the possible absence of "individualisation." It is illogical to justify the general case for such research from the exceptional event of identical twinning which occurs in only four of every 1000 deliveries. Moreover all the available evidence indicates that the capacity to twin, which is restricted to the first seven days of human development, is genetically determined at the time of fertilisation.
If after successful fertilisation of a human ovum by a human sperm the product was not immediately alive and human it would be of no value to those who wish to pursue destructive human embryo research. The presumptive benefits of such research can never justify the killing of living members of the human species.
The author is a Senior Lecturer, Department of Anatomy at the University of Manchester Medical School and a Governor of the Linacre Centre. The Linacre Centre is a registered charity dependent on voluntary donations and grants. Donations will be gratefully recived by Hon Treasurer John Soya, 9 Knoll Rise, Orpington, Kent BR6 OEJ.