Should PGD be used for elective gender selection?

Yes. Benefits for family balance outweigh potential risks 

By John A. Robertson, JD

Mr. Robertson is the Vinson & Elkins Chair in Law at the University of Texas School of Law, Austin.

Any talk of sex selection is charged because so many questions are wrapped up in the issue. The methods that may be used--preconception sperm selection, preimplantation embryo screening, and abortion--vary in their efficacy, cost, and moral acceptability. Globally, sex selection is generally used to avoid the birth of females, so the impact on population sex ratios and the role of women in society must be considered. The limits to procreative liberty also have to be discussed. Finally, from the perspective of human dignity, we also should consider whether we should accept yet another technological incursion into how we make families.

For physicians who treat patients using assisted reproductive technology (ART), sex selection poses a special challenge. In vitro fertilization (IVF) is used to treat infertility, and preimplantation genetic diagnosis (PGD) is employed to avoid the birth of children with serious genetic diseases. Sex selection for nonmedical reasons raises questions about why IVF should be used for this purpose. Indeed, the American Society for Reproductive Medicine (ASRM) says that PGD for sex selection should be discouraged. Unless a woman is already undergoing IVF for other reasons, sex selection requires a stimulation cycle solely for this purpose. Also, embryos will be created and destroyed because of their sex alone.

Issues of family balance

I find it useful when unraveling these ethical issues to give strong weight to family balancing (that is, gender variety). Freedom to decide to reproduce or not is important, and should be respected unless there are compelling reasons to limit that freedom. This means that some choice over the genetic characteristics or other characteristics of offspring is included in that liberty, because it is precisely those characteristics-and the expected experience of raising those offspring-that will help couples to decide whether to reproduce.¹

Once we accept that some degree of prebirth choice over a child’s characteristics is acceptable, we must then address the harm that this choice might cause. In the United States, we do not need to fear that PGD for sex selection will upset sex ratios or further entrench patriarchy. Women are treated equally before the law and have ample opportunities for education and employment as well as nearly equal treatment in most relevant respects. Nor is the child likely to be harmed, as long as the technique is medically safe. Even without sex selection parents have expectations for their children that may vary with its sex. Sex selection alone is not likely to drastically increase those expectations, or do so in a way that is unduly harmful to the chosen child.

Gender bias and gender variety

With controversy still surrounding the issue of sex selection, however, a reasonable way to proceed is to allow parents to select a child that is the opposite sex of one or more of their existing children. The idea here is to introduce gender variety into a family. Rearing boys is a different experience from rearing girls, and I find it reasonable that parents would desire both experiences. Interestingly, it is often the female partner who is motivated to this end, so that she might, for example, have a girl after one or more boys. Justice Ruth Bader Ginsburg, who has strong feminist credentials, wrote in a landmark sex discrimination case that “inherent differences between men and women, we have come to appreciate, remain cause for celebration.”²

Physicians should not be required to be involved in PGD for gender variety, but I do not find it unethical if one chooses to do so. Selecting the gender of a first child, particularly if the choice is for a male, raises other issues, because of the advantages that some persons think accrue to the first-born from greater parental investment in its rearing and well-being. While opting for a first-born female may not pose the same entrenchment-of-patriarchy problems as opting for a first-born male, initially sex selection for gender variety should be limited to second-born and subsequent children. For the time being, using IVF and PGD for the purposes of achieving gender variety poses no risk of serious harm to offspring, society, or women. Use of ART and PGD to choose a child of a different sex than existing children should be acceptable.

References

1. Robertson JA. Assisting reproduction, choosing genes, and the scope of reproductive freedom. Geo Washington L Rev. 2008;76(6):1490-1513.

2. United States v Virginia, 515-US-518 (1996).

NEXT: ELECTIVE SEX SELECTION IS A SLIPPERY SLOPE  >>

No. Elective sex selection is a slippery slope

By Timothy Hickman, MD

Dr. Hickman is the Medical Director at Houston IVF, Texas, and a Clinical Associate Professor at both the Weill Cornell Medical College--the Methodist Hospital, Houston, and the University of Texas Health Science Center, Houston.

Interest in gender selection has a long history, dating to ancient times. Methods have varied from special modes and timing of coitus to the practice of infanticide. Only recently have medical technologies made it possible to attempt gender selection of children before embryo implantation or even conception. In my opinion, preimplantation genetic diagnosis (PGD) used for gender selection to prevent the transmission of serious genetic disease is ethically acceptable. It is not inherently gender-biased, bears little risk of consequences detrimental to individuals or to society, and is a use of medical resources for reasons of human health.

The question is: Should PGD be used for elective gender selection? Members of the ethics committees of the American Society for Reproductive Medicine (ASRM) and the European Society of Human Reproduction and Embryology (ESHRE) have thought long and hard about this topic, and the latest ASRM Ethics Committee publication on sex selection states, “The initiation of in vitro fertilization (IVF) with PGD solely for sex selection holds even greater risk [than medically indicated PGD] of unwarranted gender bias, social harm, and the diversion of medical resources from genuine medical need. It therefore should be discouraged.” ¹ The ESHRE Task Force on Ethics and Law states, “the embryo is owed respect as a symbol of future human life.”²

The 4 areas of concern that I have about non-medically indicated use of PGD for gender selection are: (1) the potential for harm to the embryo in order to obtain the desired information; (2) gender bias; (3) the use of medical resources for reasons other than human health; and (4) the disposition of the normal embryos of the “undesired” gender.

Potential for harm to the embryo

The only reliable technique for determining gender before implantation is embryo biopsy at the cleavage or blastocyst stage. Unfortunately, prefertilization techniques such as sperm centrifugation and flow cytometry are either ineffective (sperm centrifugation) or not available for elective gender selection (flow cytometry, ie, MicroSort). Both embryo biopsy techniques carry intrinsic risk to the future well-being of the embryo being analyzed. It is hard to calculate a precise risk of the procedure but a recent publication by Treff et al³, in which sibling cleavage-stage embryos or sibling blastocyst-stage embryos were transferred with or without biopsy, suggested that cleavage-stage embryo biopsy decreases embryo viability by 40%, which in my opinion is far too great a price to pay for the information obtained. The authors calculated that biopsy of blastocyst-stage embryos (also known as trophectoderm biopsy) decreases embryo viability by 4%. Furthermore, reliable DNA sequencing techniques to ascertain accurate results (microarray, real-time PCR, etc.) often take longer than 24 hours; hence, the implantation phase is often missed, and embryos often need to be frozen and subsequently thawed. The freeze/thaw process also undoubtedly has some detrimental effect on embryo viability, since it is illogical that freezing and subsequently thawing an embryo would increase its viability. I am willing to concede this point because I think it is likely that in the near future the science of biopsying, freezing, and thawing of embryos will evolve to the point where little to no risk will exist.

From gender bias to social dysfunction

We need not look any further than the current state of affairs in China to see the result of extreme gender selection. Given the Chinese government's mandate of only 1 child per family and a bias toward male children, approximately 30 million more men than women will reach adulthood by 2020.⁴ These men have 2 options: find partners abroad or become "bare branches"--as the Chinese expression goes--unlikely ever to bear fruit. I think that it is extremely unlikely that the use of PGD for gender selection in the United States would lead to anything like China's current situation, but I have a hard time whole-heartedly supporting a policy that could, if taken to extremes, result in such social dysfunction.

Use of medical resources for non-medical reasons

I will leave this argument for the economists and health resource allocation experts. Suffice it to say that the use of IVF in the United States as well as abroad is, at least to some extent, subject to "free market" economics. Until insurers worldwide recognize infertility as a disease state and begin to cover IVF for medical indications, patients have to pay at least some, if not all, of the costs on their own, as is the case with cosmetic plastic surgery and other procedures that are deemed to be elective.

Disposition of normal but 'undesirable' embryos

The disposition issue is the hardest issue to resolve because this technique invariably produces embryos that are ultimately "undesired." If we are to uphold the ethical tenet that “the embryo is owed respect as a symbol of future human life," an adequate answer to the disposition question must be found before the intentional creation of "undesired" euploid embryos. What troubles me most is a scenario in which a couple uses PGD for gender selection and creates embryos that are all of the “undesired” gender, and then discards them. Whether the solution will be attempted use of all euploid embryos by the genetic parents or by nongenetic parents through embryo donation, donation of all undesired embryos to research, or something else, the default destruction of a large percentage of euploid embryos seems to me to be the wrong answer.

Ethics may limit 'reproductive freedom'

Reproductive freedom has never been considered an absolute right, and certainly not if it is extended to include every sort of decision about reproduction or every demand for positive support of a person’s reproductive decisions. Still, serious reasons must be provided to justify a limitation on reproductive freedom. Therefore, weighing opposing positions on PGD and gender selection depends on an assessment of the strength of various reasons given for and against it.¹

Of the 4 concerns about PGD for gender selection I have presented, the issue of disposition of undesired euploid embryos carries with it the most serious ethical questions and reasons for proceeding with caution. The vast majority of medical ethicists, and the general population, agree that the use of PGD to select for traits like eye color, hair color, intelligence, height, athletic ability, musical aptitude, etc. is inappropriate. When we consider ethical concerns surrounding PGD for gender selection and PGD for trait selection they look quite similar. Moreover, if, as a society, we cannot agree upon an ethical solution on the disposition of normal embryos of “undesired” gender, I see little preventing us from traveling down the slippery slope to a potential reproductive dystopia, where potentially invasive measures are used to obtain information on preimplantation embryos (such as gender and other elective traits) without regard to societal impact. 

References

Ethics Committee of the American Society for Reproductive Medicine. Sex selection and preimplantation genetic diagnosis. Fertil Steril. 1999;72(4):595-598

ESHRE Task Force on Ethics and Law. The moral status of the pre-implantation embryo. Hum Reprod. 2001;16(4):1046-1048.

Treff NR. Cleavage stage embryo biopsy significantly impairs embryonic reproductive potential while blastocyst biopsy does not: a novel paired analysis of cotransferred biopsied and non-biopsied sibling embryos. Fertil Steril. 2011;96(3):S2.

Brooks R. China’s biggest problem? Too many men. http://www.cnn.com/2012/11/14/opinion/china-challenges-one-child-brooks. Accessed June 17, 2013.