'Repeal the 8th'

[ProfessorDavey]

I thought you meant stem cell research using human embryos.

And why on earth would you assume that Spud.

I do have human stem cells currently growing in my labs - derived from bone marrow. You do understand that not all stem cells are derived directly from an embryo.

But of course all human cells (well almost all) are driven from a human embryo if you go far enough back. But I don't understand why you should consider that it is wrong to destroy existing human embryonic stem cells. I can understand (although I don't agree) why people object to the destroying of a 5 day old human embryo to obtain those cells, but once derived (and the embryo destroyed) why would you think it necessary to keep every single cell derived alive for ever, and all their progeny. Don't forget that these cells divide every few hours, so you do the maths at to how many you might have in a year or so and think of the cost and resources needed to keep them all alive.

You're comments demonstrate scientific illiteracy as well an ethical naivety.

[Robbie]

What do you mean?

I apologise, daresay stem cells are still used from human embryos but what I meant was they are not exclusively so, as above poster has explained. Many diseases are controlled or cured by use of stem cells now which a few years ago were incurable. There's a particularly bad - painful - skin condition, can't remember the name of it off hand but it is really dreadful - which can be cured now by the use of stem cells.

Personally I see nothing wrong in taking stem cells from an embryo which is not going to progress to being a baby but we'll have to agree to differ on that one. 

The Planned Parenthood organisation in America came in for a lot of stick about that because of selling embryos but they didn't offer abortions with the purpose of giving embryos for research, they sold on embryos that women had decided to abort so were redundant anyway. The organisation needs money to keep going and abortion is only part of their work, they do help people plan their families with contraception and any sexually active person. Trump of course withdrew government funding for them (or intended to, don't know if it has happened), to get votes and support. I doubt he really cares about abortion.

[Spud]

And why on earth would you assume that Spud.

I didn't think that you were referring to destroying cells from a blood sample or suchlike, because only a fool would believe that to be wrong and I didn't think I came across as that stupid. Your original wording could have been interpreted to mean destroying a living embryo, so I assumed that's what you meant. Thanks for clarifying, though.

[Spud]

I apologise, daresay stem cells are still used from human embryos but what I meant was they are not exclusively so, as above poster has explained. Many diseases are controlled or cured by use of stem cells now which a few years ago were incurable. There's a particularly bad - painful - skin condition, can't remember the name of it off hand but it is really dreadful - which can be cured now by the use of stem cells.

I'd be interested to know if this condition can be cured using cells from a baby's umbilical cord, which apparently is effective as a source of stem cells?

[ProfessorDavey]

I didn't think that you were referring to destroying cells from a blood sample or suchlike, because only a fool would believe that to be wrong and I didn't think I came across as that stupid. Your original wording could have been interpreted to mean destroying a living embryo, so I assumed that's what you meant. Thanks for clarifying, though.

But you have failed to explain, from an ethical standpoint, why it is perfectly acceptable to destroy a blood sample (which is, of course, derived originally from a human embryo), or some skin cells growing in a lab (also originally derived from a human embryo) but not stem cells derived from a human embryo (or rather pre-embryo or blastocyst - see below).

And actually it isn't really the case that the entity that develops five days after fertilisation is an embryo, which is why those early stages are ofter referred to as the pre-embryo. Given that the embryonic stem cells in the inner mass of that structure (the blastocyst) actually go on to form the embryo (which is why they are of such interest scientifically and clinically) it is hard to argue that the embryo is already in existence at that point.

[ProfessorDavey]

I'd be interested to know if this condition can be cured using cells from a baby's umbilical cord, which apparently is effective as a source of stem cells?

There are many possible sources of cells for clinical use, via methods often call regenerative medicine. You are correct that umbilical cord stem cells are one, as are embryonic stem cells, adult stem cells, induced pluripotent stem cells (iPS cells) and loads of cells that are 'differentiated' cells rather than stem cells.

There is no magic bullet, one size fits all and as we develop these techniques one type of cell may be best for one clinical application, with a different type best for a different application. Currently we don't know which works best as there is far, far more research to be done. Research is ongoing looking at all the different cell types in labs across the world.

Therefore to ignore one particular cell type is foolish as that might be the best type and we would therefore be cutting off the opportunity to develop the best treatment.

There is another big reason why researchers use embryonic stem cells - specifically because they are the cells which form the embryo and all the tissues in our body eventually. That reason is to study the earliest developmental processes, and in particular what goes wrong in many congenital diseases. That research cannot be carried out using adult stem cells or umbilical cord stem cells as their developmental stage is too late and for umbilical cord stem cells aren't actually part of the developing baby.

Another obvious problem with umbilical cord stem cells is more pragmatic - unless you have had them banked down at birth, there isn't a person-specific cell source available. And for the vast, vast majority of us we don't have our umbilical cord stem cells banked down and can, obviously, we can never remedy that.

[Spud]

But you have failed to explain, from an ethical standpoint, why it is perfectly acceptable to destroy a blood sample (which is, of course, derived originally from a human embryo), or some skin cells growing in a lab (also originally derived from a human embryo) but not stem cells derived from a human embryo (or rather pre-embryo or blastocyst - see below).

Just to confirm that yes it is acceptable to destroy, for example, a blood sample: you are not taking a human life. The issue here is that when stem cells are taken from the blastocyst, that blastocyst is then destroyed. Would you agree that you and I were once blastocysts, which if destroyed would have resulted in you and I being killed? No other blastocysts would have grown to become you and I. Therefore destoying a blastocyst is taking a human life.

There are many possible sources of cells for clinical use, via methods often call regenerative medicine. You are correct that umbilical cord stem cells are one, as are embryonic stem cells, adult stem cells, induced pluripotent stem cells (iPS cells) and loads of cells that are 'differentiated' cells rather than stem cells.

There is no major bullet, one size fits all and as we develop these techniques one type of cell may be best for one clinical application, with a different type best for a different application. Currently we don't know which works best as there is far, far more research to be done. Research is ongoing looking at all the different cell types in labs across the world.

Therefore to ignore one particular cell type is foolish as that might be the best type and we would therefore be cutting off the opportunity to develop the best treatment.

There is another big reason why researchers use embryonic stem cells - specifically because they are the cells which form the embryo and all the tissues in our body eventually. That reason is to study the earliest developmental processes, and in particular what goes wrong in many congenital diseases. That research cannot be carried out using adult stem cells or umbilical cord stem cells as their developmental stage is too late and for umbilical cord stem cells aren't actually part of the developing baby.

Another obvious problem with umbilical cord stem cells is more pragmatic - unless you have had them banked down at birth, there isn't a person-specific cell source available. And for the vast, vast majority of us we don't have our umbilical cord stem cells banked down and can, obviously, we can never remedy that.

Thanks for this info.

[ProfessorDavey]

Just to confirm that yes it is acceptable to destroy, for example, a blood sample: you are not taking a human life.

Define what you mean by 'a human life'.

The issue here is that when stem cells are taken from the blastocyst, that blastocyst is then destroyed.

True.

Would you agree that you and I were once blastocysts, which if destroyed would have resulted in you and I being killed?

I disagree - you and I didn't exist until a stage way after the blastocyst, because none of the key features that define personhood are present in the blastocyst. And how can a single blastocyst be 'me' if, in the case of identical triplets, it is also Tom and Jack too. You cannot ascribe continuity in personhood until the possibility of twinning has passed.

The blastocyst is not a person, true it could potentially develop into a person given the right conditions, which would include implantation into a receptive uterus. But then so could a specific oocyte (egg cell) and spermatocyte (sperm cell) give the right conditions which would include one fertilising the other.

So it is true that were that blastocyst to be destroyed then you or I wouldn't have existed (just as is the case had that oocyte and spermatocyte been destroyed). However it isn't true that destroying that blastocyst resulted in you or I being killed, because at that point neither you nor I existed as persons. So we can't be killed if we don't exist yet.

No other blastocysts would have grown to become you and I. Therefore destoying a blastocyst is taking a human life.

No other oocyte and sperm could have become you and I so is destroying an oocyte and a spermatocyte 'taking a human life'. And actually I would argue against you on the basis of personhood - personhood is much more than mere genetics. Personhood is about neurological continuity and therefore it is pointless to try to ascribe continuity relevant to personhood to any stage before neurological development has started.

So sure a blastocyst can potentially develop into a person, but so can an oocyte and spermatocyte, but to claim that blastocyte to be a specific person makes no sense biologically or metaphysically.

[Spud]

Prof, of course a person's individual characteristics aren't present as a blastocyst, and their genetic makeup wil be influenced by the environment. But can you still say it is human life - egg and sperm on their own are not, but once fertilization occurs that is an individual human?

[ProfessorDavey]

Prof, of course a person's individual characteristics aren't present as a blastocyst, and their genetic makeup wil be influenced by the environment. But can you still say it is human life - egg and sperm on their own are not, but once fertilization occurs that is an individual human?

Easy to make those kinds of naive simplistic statements - but they simply crumble to dust when subjected to scrutiny from either a biological standpoint, or an ethical one.

You make the glib statement that 'once fertilization occurs that is an individual human' - yet you don't justify at all and indeed you can't. As I have pointed out several times you cannot justify that statement as it might be 2 or 3 people, of even (rarely) 2 fertilised eggs could become one person via embryo fusion. Looking forward you cannot ascribe personhood continuity between a zygote (fertilised egg) and a specific individual person for the reasons I've stated. And the only tenable conclusion is that the zygote is not an individual human, let alone a person, but has the potential to develop into one (or more than one). So destroying a zygote (or a blastocysts) isn't killing a individual human or person.

Trust me I have looked into these issues in depth - indeed I have even published papers on it. I have read very widely, with in the scientific literature (my main profession) but also from an ethical standpoint which I have also studied in depth and published on. I've read many articles that make the kind of non-justified hand waving statements that you do and also the articles that demonstrate those glib statements to be completely unjustifiable from first principles.

[Spud]

So killing a blastocyst could be killing more than one life. Evrn worse.

[ProfessorDavey]

So killing a blastocyst could be killing more than one life. Evrn worse.

No - it isn't killing any life, as life (in the ethically important sense of personhood) hasn't started yet. You could just as well claim that killing a million sperm cells is killing a million people. Both are non-sense.

You can tie yourself up in knots all you like about the problems of trying to assign the moment of conception (itself non-sensical as conception or fertilisation is a process) as the point at which ethically significant human life (personhood) starts but any argument is easily rebuffed and has been by far more eminent commentators than you and I for decades.

The blastocyst isn't a person, it isn't you or I any more than the egg and sperm is you or I - destroying it may mean that you or I don't come to exist, but that isn't the same as killing us.

[Spud]

At what point does it become 'a human' though? Surely there is no distinguishable point after conception. An egg or a sperm cannot develop into a human. A blastocyst can.

[Spud]

No - it isn't killing any life, as life (in the ethically important sense of personhood) hasn't started yet. You could just as well claim that killing a million sperm cells is killing a million people. Both are non-sense.

This is nonsense. Of course it is killing a living organism. A sperm is part of the father and an egg is part of the mother. Both are unable to develop any further. Once fertilization occurs the zygote starts to develop as an individual separate from its parents. Just as a boy is not a man but is still a human, a fertilized ovum is an individual living human organism, no different in nature from an adult human.

You can tie yourself up in knots all you like about the problems of trying to assign the moment of conception (itself non-sensical as conception or fertilisation is a process) as the point at which ethically significant human life (personhood) starts but any argument is easily rebuffed and has been by far more eminent commentators than you and I for decades.

Now you are talking about ethically significant human life, I can think of a possible reason why using blastocyst stem cells it would be ethical, and that is because if you had a situation where you could save either a woman or her unborn child, it may be that the woman could be said to have more right to live than the baby. However, this is hypothetical and I cannot think of any examples - some may exist though. Given this situation, you might compare it to saving the life of a person with an incurable disease using stem cells of a blastocyst.

The blastocyst isn't a person, it isn't you or I any more than the egg and sperm is you or I - destroying it may mean that you or I don't come to exist, but that isn't the same as killing us.

See above.

[ProfessorDavey]

This is nonsense. Of course it is killing a living organism.

No it isn't.

In a biological sense an organism is defined as any individual living thing that can react to stimuli, reproduce, grow, and maintain homeostasis. A zygote (or blastocyst) isn't an organism as it has no ability to go any of those things in isolation from the mother. It is not self maintaining.

A sperm is part of the father and an egg is part of the mother. Both are unable to develop any further.

Nor can a zygote or blastocyst - it is no more able to independently develop further than a sperm or egg. Both are entirely dependent on certain steps outside of their independent autonomy to develop.

Once fertilization occurs the zygote starts to develop as an individual separate from its parents. Just as a boy is not a man but is still a human, a fertilized ovum is an individual living human organism, no different in nature from an adult human.

But development after a few days of basic cell division, is entirely dependent on external factors provided by the mother. A blastocyte cannot develop further alone and certainly not into a person.

[ProfessorDavey]

At what point does it become 'a human' though? Surely there is no distinguishable point after conception.

There are plenty - first those that are critical to the ability to develop further - most notably implantation. And then intrinsic features and their development that are relevant to personhood. The most obvious being first gastrulation (and formation of the primitive streak) which defines the axis of the forming embryo and actually defines whether one or more embryo will form. But perhaps more relevant is neurulation and the development of the nervous system and the brain. We are comfortable with the concept of brain death - that when brain function is irreversibly lost - that the person is dead, regardless of whether other physiological processes might be able to be maintained, perhaps artificially. So the same would apply to 'brain birth' that a person comes into existence when certain relevant neurological functions develop.

An egg or a sperm cannot develop into a human. A blastocyst can.

Yes they can - in both cases certain necessary and sufficient inputs need to happen - sure there are slightly less for a zygote than for a sperm or egg (the later two needing to engage in fertilisation) but in both cases there is the possibility that they can develop into a human.