Couples Cull Embryos to Halt Heritage of Cancer
By subjecting Chloe to a genetic test when she was an eight-cell embryo in a petri dish, Mr. Kingsbury and his wife, Colby, were able to determine that she did not harbor the defective gene. That was the reason they selected her, from among the other embryos they had conceived through elective in vitro fertilization, to implant in her mother’s uterus.
Prospective parents have been using the procedure, known as preimplantation genetic diagnosis, or P.G.D., for more than a decade to screen for genes certain to cause childhood diseases that are severe and largely untreatable.
Now a growing number of couples like the Kingsburys are crossing a new threshold for parental intervention in the genetic makeup of their offspring: They are using P.G.D. to detect a predisposition to cancers that may or may not develop later in life, and are often treatable if they do.
The next step is to modify genes themselves, i.e., to bear children that have gene variants that neither parent possesses. If this does occur, then our evolution will increasingly be driven not by the demographics of childbirth, but by our social ideals.
Will parents continue to bear children the old-fashioned way, when their neighbors are making sure that their children are as disease-free as possible, and as close to social ideals of perfection as technology allows? Or, will all babies, at least in affluent societies be born through the test tube?
And, what happens to ideas of kinship, once your children do not possess 50% of your genes, but x% of your genes and (50-x)% of genes picked from a catalogue?
Perhaps, the next stage of evolution will not be driven by selfish genes manipulating human bodies to perpetuate themselves, but by symbiotic meme-gene complexes, where memes manipulate brains to select genes for one's offspring, and genes create brains conducive to such manipulation.
But, will our drive to create perfect offspring, perhaps eliminate that little bit of weirdness which is responsible for all high human creativity?