Monday, September 16, 2013

Human brain reproduction

Scientists have taken significant steps toward creating a human brain in the laboratory. Using stem cells, scientists have grown clusters of brain cells about the size of a BB that display characteristics of key areas including the hippocampus and cerebral cortex and are reminiscent of a nine-week-old fetus' brain. The work offers possibilities for individualized drug testing and probably paves the way for further developments. (Laura Sanders, "Tiny human almost-brains made in lab," Science News, August 28, 2013)

This research pushes the work done with mouse brains, reported in a previous Ethical Musings post, even closer to sharp ethical issues.

Humans have found modifying human brains morally acceptable. Drugs can temporarily alter a brain's functioning, sometimes legally and beneficially (e.g., an antidepressant, an effort to prevent seizures, or to dissolve a brain clot) and sometimes illegally and of questionable benefit (e.g., illegal hallucinogenics). Surgery can permanently alter a brain or its functioning, sometimes beneficially (e.g., to remove a clot or stop seizures) and sometimes of questionable benefit (e.g., lobotomies to end depression).

Is the creation of a human brain morally acceptable?

For example, could brain replacement one day enable a brain-dead person to live again? Although the body with the replacement brain would be the same, perhaps even hosting a brain identical to the person's brain at birth, the experiences recorded in the brain – which change the brain – would be different. The replacement brain would have no memories or information about the person's previous experiences, relationships, learning, etc. The person, in very many ways would be and always remain a different person than before the brain trauma that preceded the replacement. Brain replacement will not enable the brain-dead to live again.

Alternatively, could creation of a human brain represent a new frontier in human reproduction, substituting a brain (and perhaps the rest of the body) grown in a lab for sexual reproduction? This option has at least two major ethical problems.

First, asexual human reproduction through cultivation of stem cells in a laboratory carries with it all the disadvantages of most forms of asexual reproduction by narrowing the gene pool. Nor is it apparent that people who could both afford and would choose this form of reproduction represent either the best of Homo sapiens or the preferred path for the species' future.

Second, asexual human reproduction through cultivation of stem cells in a laboratory also establishes the potential for genetic manipulation by the scientists responsible for the process. Not only are the potential effects of that manipulation exceedingly unpredictable given our limited understanding of how thousands of genes interact with one but it is also not obvious that humans have the moral wisdom or can look sufficiently far into the future to make choices about the best path of human development.

In sum, growing a human brain from stem cells puts the creature in the creator's role: God set human sexual reproduction in motion through choosing to create the cosmos using evolutionary processes; altering something that basic is so fraught with unknown and unknowable dangers that it would be an act of human hubris.

Incidentally, other researchers have recently reported that poverty or wealth effects the brain's functioning: in general, the affluent function better cognitively than do the poor, perhaps, the researchers speculate because the poor's worries about finances disrupt occupy their thoughts. The effects seem reversible. Coming into sudden affluence restores cognitive functioning to its pre-poverty level. (Bruce Bower, "Poverty may tax thinking abilities," Science News, August 29, 2013)

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