Sex selection

Following ethical issues, many of unwanted pregnancies and abortions can be avoided. Several factors such as cultural, social, religious, and economic issues, as well as medical reasons such as the existence of some diseases related to chromosome X encourage couples to choose traditional or new treatment methods for selecting their child’s gender. The establishment of family balance is another reason for selecting the gender of the child.

Now there are several laboratory methods for determining fetal sex before implantation:

• Preimplantation genetic diagnosis (PGD) - Prior to fertilization with IVF, the fertilized eggs can be genetically biopsied with PGD to increase fertilization success. Once an embryo grows to a 6-8 cell size, a small laser incision in the egg membrane (zona pellucida) allows safe removal of one of the cells. Every cell in the embryo contains an identical copy of the genome of the entire person. Removal of one of these cells does not harm the developing embryo. A Geneticist then studies the chromosomes in the extracted cells for genetic defects and for a definite analysis of the embryo’s gender. Embryos of the desired sex and with acceptable genetics are then placed back into the mother. 
• Preimplantation genetic screening (PGS) - The intention of PGS is to improve live birth rates after IVF treatment by exclude embryos with aneuploidy prior to transfer. The development of advanced technologies allows analysis of all 23 pairs of chromosomes (22 pairs of autosomes and the 2 sex chromosomes) known as "24 chromosomes" analysis. Gender selection may be a part of the routine PGS embryo analysis.
• The Ericsson method - The Ericsson method separates male and female sperm by passing them through a column filled with blood protein, human serum albumin. As the sperm enter the human serum albumin, the differences in mass between the X and Y chromosomes manifest as the lighter male sperm push deeper into the protein than the females dragged down by the weight of the extra "leg" of the X sex chromosome. This tiny difference creates separate layers of concentrated male and female sperm. The layers of gender-selected sperm are of higher concentrations but not pure. This lack of purity explains the 30% chance of gender selection failure of the Ericsson method. It is simple, cheap, and practical without using any toxic material. The gradient albumin method, which includes passing sperm from human albumin layers to separate the sperms containing Y chromosome in two different layers. The lighter Y sperms which move faster than the X sperms pass through the layers of human serum albumin and residue in the laboratory tube. 
• Sperm sorting (MicroSort) - Sperm sorting is a means of choosing what type of sperm cell is to fertilize the egg cell. It can be used to sort out sperm that are most healthy, as well as determination of more specific traits, such as sex selection in which spermatozoa are separated into X- (female) and Y- (male) chromosome bearing populations based on their difference in DNA content. The resultant 'sex-sorted' spermatozoa are then able to be used in conjunction with other assisted reproductive technologies such as artificial insemination or IVF to produce offspring of the desired sex.
• Swim up - a simple method of modified swim up that is based on the movement of sperm and done within a few steps. Although, the success rate of this procedure to achieve male sex and female sex have been reported to be 89% and 86%, respectively; other researchers did not report a specific comment about the efficiency of this technique.

Legal aspects

In 36 countries there is legislation against sex selection using ART, including 25 European countries. Legislation prohibits the use of PGD for sex selection under all circumstances (e.g., Austria, Germany and Switzerland), or limits its use to medical purposes (e.g., the UK, France, Norway, Spain, New Zealand, India). In the United States, in contrast, the use of this procedure is not prohibited by law, and couples who are interested can freely approach a specialist clinic. In Israel, sex selection for medical reasons is included in the basic benefits package to which all Israelis are entitled, within the framework of National Health Insurance (Pic. 1). In addition, hospital-based pregnancy termination committees in Israel are authorized to approve abortions related to sex selection for medical reasons.

Ethical aspects

The ethics of gender selection for non-medical reasons touches on many important areas. Concerns about human dignity and respect for all persons, and the reinforcement of gender role expectations and sexist motives inform the debate. Gender selection invariably leads to discussion about the limits of procreative liberty, and the “slippery slope” leading to designer babies, where PGD may be used to select traits like eye color or height. Other issues raised are about the health of the offspring chosen by sex selection and whether undue expectations of such children may be harmful. IVF confers (small) risks to mother, hefty costs, and embryos which will be created and then destroyed only because of their sex, clearly disturbing to those who believe, as the ESHRE Task Force on Ethics and Law stated “the embryo is owed respect as a symbol of future human life”.
Opponents to limiting gender selection through PGD consider concerns about sexist discrimination or entrenching patriarchal values as being largely symbolic, and limiting sex selection infringes on reproductive freedom and self determination. Evidence for distorted sex ratios in Western countries, or harm to child selected is lacking, and thus gender selection through PGD should be allowed.

Many families request sex selection for family balancing, selecting an embryo that is the opposite sex of one or more of their existing children. The goal is for gender variety in a family, and is frequently motivated by the female partner, and thus is not inherently sexist, as it may be motivated by the desire to rear children of both genders.

Sex selection provides a preconception reproductive option for parents wishing to reduce sex-linked and sex-limited disease risk for their future children. Prevention of selective abortion, physical lesions and psychological woes of mothers and families, overpopulation, as well as paying attention to the optimal social and psychological factors in balanced families, are additional reasons for paying attention to the methods of gender selection before conception (Pic. 2).

Family size and composition have been considered a major motivator for sex-selection. Many studies, including studies in Israel, have indicated that in families where there are children of a single sex and especially in cases of at least three of the same sex, there is clear preference for the other sex. The association between family composition and preference for offspring’s sex is not surprising given the ongoing trend of declining total fertility rate in Western countries, as well as in Israel. An Israeli study regarding attitudes towards PGD included a survey among a population of married couples of reproductive age who were parents to at least two children of only one sex. In their sample it was found that 45% of the respondents supported permitting sex selection for non-medical reasons and 42.6% wished to select the sex of their own future child. However, many of those expressing opposition in principle were willing to allow this in cases of psychological or familial crisis.

One of main problems of PGD is that it can’t assure absence of genetic or congenital disorders in born infant, and the infant is devoid of that disease that were tested. Another complication is that gender selection results in “loss” of approximately half of all embryos (the undesired sex). In fact it is believed that PGD causes creation of unisexual creatures and destroys opposite sex. 

Selection of the child’s sex for non-medical reasons (such as religious, financial, emotional, and/or family sex-balance considerations) is highly controversial. There is real and imminent risk of significant damage to the mental health of one or both parents, or to the expected child, if the procedure is not conducted. Sex selection because of non-medical leads to imbalance in gender of the population and male:female ratio. Opponents of PGD for non-medical reasons claim that free use of medical technology for sex selection may lead to:

• danger of upsetting the demographic balance between the sexes, as in India and China, where abortion of female fetuses has resulted in a lack of millions of women
• danger of the “slippery slope” whereby fetal sex selection is the first step toward “custom made babies”, and unprecedented interference in the act of creation
• psychological harm to the “custom made child” who must withstand the pressure of meeting parental expectations, and concern for damage to other children in the family
• discrimination against women by diminishing their very existence
• the inevitable destruction of pre-embryos
• medical risks to the mother and offspring as a result of technological methods employed
• inappropriate and potentially unfair use of limited medical resources

In methods based on sperm sorting methods (MicroSort, Ericsson method) not all participants are able to provide raw semen specimens of sufficient quality for sorting. Approximately 3% of sorts are cancelled for a variety of reasons, primarily related to semen quality: insufficient sperm numbers (<140 × 106 sperm for IUI sorts and <70 × 106 sperm for IVF/ICSI sorts) or motility (<50% motility) in the raw specimen; insufficient sperm recovered after processing, often due to extremely high degree of debris in the specimen; and/or poor sperm survival after processing.

However, the MicroSort technique, for example, by using flow cytometry device is not risk-free, let alone the cost of the relevant instruments and the imposition of heavy medical expenses to the couple. In MicroSort method, the sperms are stained with toxic fluorescent materials, under the x-ray machines that these factors are worrying. The application of this method had been evaluated more in animal reproduction as well as conditions such as genetic diseases dependent on X chromosome.

Another aspect of the dilemma involved in sex-selection may be the emotional cost to the parties involved of promoting desire for a child of the requested sex by offering the option of choice. It is notable that almost 30% of the applicants did not complete the application process. When possibilities exist, they may open avenues of expectation, which may in turn lead to disappointment when these expectations are not fulfilled. Schwartz, considering consumer options, has called this the “Paradox of Choice”, stating that while autonomy and freedom of choice are important for well-being, Americans have more choice than ever, but do not seem to be benefiting from this psychologically. More specifically relating to reproduction, others have noted the irony inherent in the fact that new reproductive technological advances may become a source of stress by offering the option of choice. As Rothman stated: “The technology of prenatal diagnosis has changed and continues to change women’s experience of pregnancy”. McQuillan discussed the irony inherent in new reproductive technologies that open options both for women dealing with childlessness, as well as for those who do not have fertility problems, concluding that “… these choices may be yet another source of stigma and stress for women who do not choose to pursue medical treatment or to pursue it to its extreme”. The question remains as to whether the choice of sex-selection enables families to fulfill their hopes, or results in pressure on them - particularly on women - to meet expectations that have become available, or both.

From available methods used for sex selection, not every type has the same success rate. The Ericsson method has a 70-72% success rate for boys and a 69-75% success rate for girls, but this method is not widely used. It is currently being trialed on humans in the US under the trademark MicroSort; it claims a 90% success rate but is still considered experimental by the FDA. The most effective sex selection is through PGD in IVF cycles, where embryo biopsy is done at the cleavage or blastocyst stage. The PGD technique is favored over the Ericsson method because of the stricter control of the offspring gender in the laboratory. Since only embryos of the desired sex are transferred to the mother, PGD avoids the small likelihood present in the Ericsson method of an undesired sperm fertilizing the egg. Gender selection success rates for PGD are very high. The technique is recommended for couples who will not accept a child of the undesired gender. By employing the pre-implantation sex selection method, the number of unwanted pregnancies or abortions decreases and diseases related to sex can be prevented.

In cases of classical X-linked disorders, sorting for X-bearing sperm would increase the likelihood of conceiving a girl to approximately 90% and decrease the likelihood of conceiving an affected male child from 25% to 2.5%.

Leading international professional organizations have acknowledged the complex implications of the use of PGD for non-medical reasons. Several organizations, such as WHO, UNESCO and HFEA (Human Fertilization and Embryology Authority, UK), have published policy statements opposing its use. However, ESHRE (European Society of Human Reproduction and Embryology) and ASRM (American Society for Reproductive Medicine) have expressed divergent views on the issue, and note that the use of PGD for social reasons would be reasonable under certain circumstances, notably with an emphasis on family sex-balancing. ESHRE’s (2013), recent recommendations leave room for re-evaluation of blanket rulings permitting or banning non-medical PGD sex-selection, for example, in cases of those who must undergo IVF for medical reasons.