Monday, December 18, 2006

Human Reproduction: Definition of Human Embryo

Y'all didn't seriously think a little thing like my husband's left hip surgery would stop me, did you?

Human Reproduction, a peer-reviewed, high impact journal of research and opinion concerning "the scientific and medical aspects of reproductive physiology and pathology, endocrinology, andrology, gonad function, gametogenesis, fertilization, embryo development, implantation, pregnancy, genetics, genetic diagnosis, oncology, infectious disease, surgery, contraception, infertility treatment, psychology, ethics and social issues" (free, full text online in advance of pulishing) has published the following definition of a human embryo:

The following biological definition of ‘human embryo’ is proposed.

A human embryo is a discrete entity that has arisen from either:
(i) the first mitotic division when fertilization of a human oocyte by a human sperm is complete or
(ii) any other process that initiates organized development of a biological entity with a human nuclear genome or
altered human nuclear genome that has the potential to develop up to, or beyond, the stage at which the primitive
streak appears,
and has not yet reached 8 weeks of development since the first mitotic division.


There is "insufficient information whether the entities derived by parthenogenesis, gametogenesis using pronuclear DNA from two parents, and several SCNT and Chimera scenarios which - prior to their creation - have had the ability to implant removed from the genome. However, the entity would be covered by the definition if the manipulation can be said to have "the potential to develop up to, or beyond, the stage at which the primitive streak appears."

I would think that this definition would cover most of the most troublesome aspects involving regenerative medicine or destructive human embryo technique. The uncertain cases would need to be proven to not be human embryos, through animal models, or for the more unethical, actual experiments using human DNA.

Let's hear no more about "early" stem cells, or "there's no sperm(!)" or "there's no potential to form a human baby/person/be implanted in a uterus," etc.

Thank you Human Reproduction, for making this article available free. The tables, showing the need for human oocytes and the sources of DNA and cytoplasmic (oocyte) material necessary for the production of each class, are invaluable.

7 comments:

Suricou Raven said...

As far as ethics go, it seems a bit pointless to me. A few sloppy thinkers do try to wriggle free from problems with the 'its not human' arguement, but thats usually only in response to a 'all humans are sacred' arguement from the otherside - the real issue is not *if* the embryo is a real human embryo or not, but *why* humans are considered to have rights at all. Only when someone can justify giving an adult human any forms of rights or protections can they decide at what level of development the rights should be given.

LifeEthics.org said...

I always say, "Because we're the only species having this conversation."

You seem to imply that there is no basis for any rights or for society to give protection of those rights.

Suricou Raven said...

"Because we're the only species having this conversation."

See, you have a reason. I wouldn't call it the best reason, but it will do. But as embryos do not have, and are incapable of having, any conversations... it doesn't justify rights for them, any more than it justifies protecting the life of, say, a banana. If ability to communicate is the standard, then you would want to set the boundry to some point after birth - a little late I think, but at least you would have some type of reason to justify a position like that. Not merely 'But its got human genes.'

LifeEthics.org said...

And your criteria would be?

These are our children, the ones who will be having the conversation in the future.

You and I (as individual members of the species) have had this conversation several times.

It is not required for every member of a species to possess the qualities of the species, or for any to express all of them all the time.(not all need to bear children, speak with a voice, etc.)

It's not the ability to have the conversation - it's the fact that ours is the only one which deliberates on rights, protection, and choosing which members of the species will or will not be considered worthy of protection. We value certain actions more highly than others. We argue those values in order to learn, influence others, even when there's no immediate material gain, only a certain kind of ephemeral feedback we call satisfaction or happiness.

Different variables have been considered in different societies, but all have had some criteria. We look back through history and do not approve of slavery and do approve of increasing sufferage to wider classes.

Suricou Raven said...

You have an excellent arguement in favour of assigning protected status to a species. I just dont see how it can apply to individuals in the same way. You are argueing from simularity: Adult humans have rights. Therefor all things similar have rights. But in this case, an embryo is more like an animal than an adult human.

LifeEthics.org said...

If I visit certain countries, the fact that I am a woman means that I am the equivalent of an animal.

How, short of a species definition, will you define "person" in such a way that is logical, verifiable by different observers in different conditions, and which will stand up to the other discriminators?


Or which will not bring the designation of those who will be protected down to whoever has the best weapon: power, bomb, gun, law degree, legislative, regulatory, media,or religious influence, or the ability to stage a military coup or revolution by any of the above?

bmmg39 said...

"But as embryos do not have, and are incapable of having, any conversations..."

...just as newborn babies are incapable of having conversations. Using this criterion, it should now be permissible to kill newborns for medical research, eh?