With the press flooded with futuristic phantasms of using CRISPR-Cas 9 to genetically engineer "designer" children -- by creating human-induced hereditable mutations -- it's easy to lose sight of ethical, legal, and moral issues arising from currently existing technology. Will we be tempted to "improve" our genetic destiny, and who decides which improvements to make? And who gets them? Are we mature enough as a society to eschew decisions leading to claims of eugenic determinism? And what about the social justice concerns?
Most responsible embryologists claim that once safety is assured, genetic engineering would be reserved for editing deleting genetic signatures causal of disease, rather than selecting for desirable traits, like IQ or height. For now, though, that technology isn't on the table –the unintended consequences, including the risk of off-target effects and accidental deleterious mutations, are still significant concerns to overcome before we reach it. But other existing technologies with ramifications we haven't yet fully addressed are.
Consider savior-siblings - children created by enhanced in vivo fertilization, IVF, bred for the express purpose of transfusing their blood to already existing children plagued with dreaded diseases, like certain leukemias, for which hematopoietic blood transfusions are the only cure. Because an "exact" immune tissue match is required, when none can be found via a blood bank, registry, or compatible relative, parents may decide to create a compatible blood donor by creating a new baby with the requisite immune signature. Without IVF, the odds are one in four that the "savior sibling" will be an exact (HLA) tissue-match. With it, the odds close in on 90%. 
No laws forbid this in the US. Indeed, very few American regulations address IVF at all, and the ones that do exist relate mostly to the procedure's effectiveness . In the UK, the British Health and Embryology Agency strictly regulates IVF, but oversight varies in the rest of Europe , where in some countries it's legal, and others not.
The initial objective of the procedure – aggressively advocated by British bioethicists some twenty years ago when it was then illegal- was to transfuse the savior sibling's umbilical cord blood, a benign procedure. But, if that didn't work, the savior would be subjected to bone-marrow transplantation - which subjects the savior child to surgery and incident anesthesia risk, all without a guarantee the bone marrow transplant will cure the ill sibling. It's a hope, and publicized success stories are quite seductive.
If this sounds like the stuff of a good novel, it is. Jodi Picoult wrote My Sister's Keeper in 2004. Her story doesn't stop with the savior child being subjected to a bone-marrow transplant; she is then required to donate a kidney. Real-life is often stranger and even more dramatic than fiction. Six years after Picoult's book, Beth Whitehouse wrote The Match – the true story of Katie Trebing. Whitehead had a front-row seat - even attending pre-natal physician meetings and the subsequent birth of the savior child -- making for voyeuristic reading, and I, for one, question the motivation of parents who enlist a journalist to chronicle their experiences at these incipient stages. But Katie Trebing is doing well and has only required a bone-marrow transplant from her donor brother, not more. So, all seems copacetic. For now.
But what happens if a savior sibling is called upon to donate more than umbilical cord blood? When the Trebings decided to go forward, little evidence was available, and successful umbilical cord transfusion was the hoped-for objective. Fifteen years later, there is still no aggregated American data. But recently, we have limited data from Europe  which indicates that umbilical cord transfusion is successful in only 5% of the cases, and the majority
(95%) required bone marrow transplants, either alone or in combination with cord transfusion. These bone marrow transplants are typically scheduled within two years after the savior is born. In instances involving genetically induced anemias rather than cancers, no valid medical reason would prevent delaying surgery until the child was old enough to have an informed say, especially in view of a small, but important, incidence of graft vs. host reaction or transplant rejection.
A savior child could also be a potential organ source, say, of a lobe of the liver or lung or kidney. Informed consent for all these procedures, including the bone marrow transplant, vests in the parents – the same ones whose interests are, at best, conflicted. The savior child's entire existence was purposed on saving an existing sibling. Would the parent who went through the obstacles of conceiving this savior child shy away from doing "whatever it took" to save the elder child's life?
Since the law doesn't regulate the procedure, there is no oversight on parental decision-making. In cases with immune-compatible siblings born naturally, absent parental discord (usually arising in divorce cases), the courts aren't called in, nor do ethics committees or hospital oversight committees pass on the propriety of these decisions. Where courts have been called in, the American standard is that the donor sibling's best interest governs. In cases involving naturally born siblings, the leading legal decisions hold that it is never in the donor's best physical interest to donate an organ – although it might be a psychological benefit if the child is older and a relationship exists between the siblings. .
An alternative legal theory is the doctrine of substituted judgment, a concept used to make end-of-life decisions. Here, we ask what the child would do if they were capable of making an informed decision. For example, would a comatose person choose to end his or her life if they knew they were doomed to a life of pain or "vegetable" status? In a community that values life above all else, the ethical doctrine of "solidarity"  might allow an inference that the donor child would feel honored to save a sibling, even if it jeopardizes his or her own life.  But we have a long way to go before this doctrine would be invoked in the typical American community.
At the end of the day, allowing such transplants in all young children, however conceived, would be unlawful unless a psychological-bond exists between the siblings – hardly demonstrable at a year when savior sibling bone marrow donation typically occurs. Perhaps, it is time to require at least hospital ethics boards to approve all inter-sibling tissue or organ donation?
Additionally, newer medications appear to make even incompatible umbilical cord blood suitable for transplant. Shouldn't these be the required standard of care before savior children are even "conceived.?" And the cry that a parent would have had another child no matter what, rings hollow in light of data suggesting that pre-implantation biopsy, a necessary part of pre-implantation genetic diagnosis, may not be
is not without harm; and newer data reporting a small increase in congenital disabilities and subsequent cancer associated with in vitro fertilization.
Surely, where parents are unable to conceive without the technology, IVF is a reasonable risk. However, where a parent uses the procedure to help an existing child – that choice might be suspect – knowing that the child they will bring into the world may have more health risks than his/her naturally born counterpart.
The signals of this practice are especially relevant to our decision-making in CRISPR/genetic engineering. While professing disdain for selecting "enhanced" genetically engineered traits – ones we might find useful or favorable, we are doing precisely this when creating savior children and choosing a desirable immune status. The desire to improve family genetics – to select for desired traits- not just to avoid bearing diseased children is now exposed: We've failed our
own acid test of being seduced by eugenic "improvements."
 Because many of these leukemias are inherited, the embryos hormonally germinated by the IVF procedure are screened to ascertain that future children won't have the same genetic disease as their sibling. Then, the embryos are screened again to assure that they are immunologically compatible with their would-be sibling. Viable embryos filling both criteria are implanted in Mom, and presto, with lots of TLC, a savior is born nine months later.
 Naomi Cahn, Test-Tube Families, Why the Fertility Market Needs Legal Regulation, Naomi R. Cahn & Sonia M. Suter, The Art of Regulating ART, 96 Chi.-Kent L. Rev. (forthcoming 2021).
 Anver Kuliev, Svelana Rechitsky, Joe Leigh Simpson, Practical Preimplantation Genetic Testing, Social, Ethical, and Legal Aspects, Springer (2000).
 The study reviewed 14 IVF centers throughout Europe, although the preponderance of results came from one center in Turkey. Of the 365 children conceived with the intent to act as a savior sibling, only 57 (15%) served as umbilical cord blood or bone marrow donors – illustrating the paucity of data to inform parental decisions.
 Savior Siblings, Protective Progeny, and Parental Determinism in the Age of CRISPR-Cas, Social Science Research Network and Chicago Kent Law Journal, see especially Curran v Bosze 566 N.E.2d 1319 (Ill. 1990)
 Solidarity used in bioethics refers to "the willingness to give oneself for the good of one's neighbor, beyond any individual or particular interest" – a measure of collective rather than personal interest or responsibility