I started this post a while ago. The recent conversations about the sale of foetal tissue have brought all of my thoughts into sharper focus.
Advances in technology mean that we can take more and more control of the reproductive process. Embryos can be created in vitro using eggs and sperm harvested from people who may or may not be a couple.
Embryos can be tested by pre-implantation diagnosis for the absence or presence of life-limiting genetic disorders. Just one cell removed from the bundle of cells which makes up the early embryo, can be processed to reveal the genetic make-up of all of the cells. Each cell is genetically identical and at this stage is pluripotent – capable of developing into any tissue.
To overcome motility or low sperm counts, sperm nuclei can be directly injected into eggs
I have wondered for some time how long it would be before “advances” made it possible for same sex couples to be enabled to be the biological parents of a child. The ability to manipulate the pro-nuclei of gametes makes this prospect something that is very possible, as discussed in detail in this article: Are babies from same-sex couples really possible?
But let us take a step back, how does sexual reproduction ensure that each new individual is genetically distinct?
Gametes (eggs and sperm) are produced by a type of cell division known as meiosis, or reduction division. Every cell (except the gametes) in our bodies contains 23 pairs of chromosomes. One of each pair came from our mother and one from our father.
These chromosomes contain the 20,500 genes that control our appearance and physiology. Between the genes lies non-coding segments which form the bulk of the DNA and used to be thought of as mostly “junk”. However, it is now known that these non-coding segments often have essential controlling roles – the fingerprints of the creator.
Meiosis separates the chromosome pairs – one from each is allocated to an “intermediate cell” (primary oocytes and spermatocytes), but not before pieces of information have been swapped between the pairs. The intermediate cells contain a mix of chromosomes from our mother and father divide again (though not until fertilization in the case of the ovum). The result is that each gamete is has half the genetic information found in the parent cells (23 chromosomes) and this set of information is different from other gametes, no two sperm are identical, neither are any two ova.
Fertilization, whether natural or assisted, produces a fertilized egg (zygote) in which the genetic composition is truly unique. The chances of two individuals have the same genome are infinitesimally small – small enough to ignore. Only identical twins share the same set of genetic information – because they arise from the same zygote.
For You formed my inward parts;
You wove me in my mother’s womb.
I will give thanks to You,
for I am fearfully and wonderfully made;
Wonderful are Your works,
And my soul knows it very well.
My frame was not hidden from You,
When I was made in secret,
And skillfully wrought in the depths of the earth;
Your eyes have seen my unformed substance;
And in Your book were all written
The days that were ordained for me,
When as yet there was not one of them.
As a biologist I am fascinated by the advances in reproductive research; as a Christian I find myself questioning the means by which these advances are wrought. Perfecting techniques so that they can be safely used in vivo, means that embryos must be produced in vitro and destroyed by the analytical processes or discarded as surplus to requirements.
Understanding that from the moment of conception the zygote holds the potential to form all of the tissues and organs of a unique individual, at what point is this organism human?
At what point can we justify destruction of this “one of a kind” either as collateral damage in the advancement of reproductive science or abortion? Obviously the manipulations involved in same sex reproduction will of necessity involve production of embryos which will fall into these categories.
Alistair Roberts has discussed this from a theological and philosophical point of view in his blog post Abortion and Personhood. He makes the point that the difference between pro-choice and pro-life is one of relationships. If I do not want to keep my offspring then I will tend to think in terms of “it” “embryo” or “foetus”; if I am delighted to be pregnant I will think in terms of baby, from conception.
I remember the thrill of seeing the heat-beat on the 8 week ultrasound – confirming that the “embryo” was alive. At 12 weeks some break-through bleeding sent me scurrying to the maternity unit. The scan was a pure delight – not only was my baby alive and well, she (I “knew” she was a girl from very early on) was waving her arms and whooshing around like a baby in a bath-tub. Very much like this lovely video:
At 12 weeks abortion is legal and accepted as “normal”. In a wanted pregnancy this 12 week foetus is seen as a dancing baby; in an unwanted pregnancy it not seen.