A couple of weeks ago, after a group of scientists in Oregon announced that they had created a human blastocyst using techniques sometimes called cloning, something remarkable happened.
Just two or three years ago this development would have reverberated through our political culture, stiffening the spines of social conservatives and causing acida within the diverse life sciences advocacy world, tensions I catalogued in my book, The Body Politic.
To be sure, the usual suspects on all sides weighed in, some objecting to the experiment as an important step toward human reproductive cloning, others noting the need for better sources of human cells for research. The latter folks held their breath, hoping for as little blowback as possible, especially considering the current budgetary pressure on the NIH and the dearth of private investment in stem cell research.
But, beyond the small policy community that is deeply invested in these kinds of issues, the ripples barely got off the beach.
How to explain an ideological non-event? It might be that so-called cloning for research is gradually being normalized in the public mind, which has learned to distinguish it from cloning for reproduction.
Despite some confused media reports, the Oregon scientists did not clone a human embryo but a blastocyst that lacks some of the cells needed to implant in a uterus. Their goal was to produce cells that would be compatible with the person who was the source of DNA inserted into a human egg. Using a cocktail of chemicals they succeeded in obtaining various cell types, including beating human heart cells. Systems like these may someday be used to treat human patients by introducing healthy tissues to take over from diseased cells.
Ever since the cloning of Dolly, observers have expected that a similar process could in theory be used to produce a human embryo. The basic concept -- removing the nucleus from an egg cell and inserting the DNA from a skin cell -- was obvious enough, but it took hundreds of attempts and many deformed fetuses and dead ewes to produce one successful birth. It has been suggested that Dolly's relatively short life span might have had something to do with the fact that her DNA was "older" than she was, but that is only speculation.
The technical challenges for cloning a human blastocyst include the fact that human eggs are very fragile and their internal processes are hard to control. So it was thought that hundreds of human eggs would have to be used, which was both scientifically and practically untenable, especially for widespread laboratory use of any cell products. But once the Oregon team found the "recipe" for controlling that process, they were able to produce the cloned human blastocysts at a surprisingly high level of efficiency, which is very good news for possible future therapies. High on the list are Parkinson's, multiple sclerosis, heart disease and spinal cord injuries. The so-called induced pluripotent stem cells (iPSC's) that a Japanese group figured how to make from ordinary body cells in 2007 are already being used in many labs to study the genetics of these diseases, along with cells from the most controversial source: donated human embryos.
So there are now three sources of cells that could become any of the more than 200 cell-types in the human body: human embryonic stem cells, induced pluripotent stem cells, and the new cloned blastocysts. In principle one would expect stem cell biologists to take the next few years to compare the usefulness of cells from each source -- if they have the funding.
Back to the public's gradual acceptance of this science: A great philosopher said that the future tends to resemble the past. Lesser minds than David Hume (and that's just about everybody) have focused mostly on the "tends to" part of that wise remark. But much also depends on what one means by "the past." In this case the relevant past could have been the cloning of Dolly the sheep in 1996, which led to loud presidential opposition to human reproductive cloning and a decade of culture wars redux.
Instead, it seems the relevant past is the decade following the first "test tube" baby in 1978. First seen as "Frankenbaby" in the tabloids, in vitro fertilization became normalized. Now over a million babies have been born as the products of IVF. It may well be that cloning for stem cell research has become normalized in the public mind.