There’s another way to think about this kind of testing, and I’m interested in opinions about this approach. The technology now exists to ‘correct’ small mutations in the genome (generally less than 10 base pairs) by specifically targeting those regions for corrective recombination. It’s still relatively early on for these approaches, but there is zero question that they can correct gene mutations.
It is therefore feasible to do genetic testing for correctable DNA point mutations relatively early in pregnancy, take out pluripotent (’stem cells’) from the amniotic fluid or other fetal source, correct the mutation in those cells, and then reintroduce those cells to the fetus. There are lots of hurdles for this to work, but it is technically feasible. It would not correct the defect in all cells in the baby, but done early enough in development could result in a large enough percentage of cells having the normal gene to prevent manifestation of the gene mutation.
What are your thoughts about the ethical aspects of this?
That kind of approach would be technically very difficult.
First, you’d need to know exactly what the genetic defect is (and, among billions of base-pairs, that isn’t trivial). The only way we know now is by specifically looking for known defects.
Then, you would have to devise a delivery system for the corrective DNA. There are several options for this, but the efficiency would probably depend a lot on the stage of pregnancy. And it would be difficult to target the fetus in a non-invasive manner; an invasive manner would risk killing the fetus.
I’m not sure that anything that intentionally and specifically targets the DNA with the goal of changing the sequence is ever going to fly, even if it were possible. Ethically, people would be against it. Medically, good luck getting it through the FDA—even if you could get the FDA to approve one treatment for one specific condition, the FDA won’t automatically extend that to similar treatments for other conditions.
Right now, it is possible to examine blastocysts prior to implantation in IVF clinics. New techniques are being developed; one was published recently in Science that looks very promising in being able to select blastocysts that have the highest chance of implanting and growing into a baby. But, even with those techniques, some sort of adverse genetic condition can still get through.
I have no particular ethical concerns regarding early products of conception—they have no organs, no nervous system, no awareness, and really are just clumps of cells responding to a series of instructions. But I think there are people who would have strong objections to such manipulations.