Maintaining an adequate sperm donor pool: modifying the medical criteria for sperm donor selection

Abstract

The shortage of donor sperm will increase due to greater access by lesbian couples and single women and due to extra rules imposed on sperm donation. Two steps should be distinguished in donor recruitment: an ethical phase where candidates are self-selecting on the basis of ethical rules, and a medical phase where criteria related to quality and safety of the sperm are imposed. The first phase functions as a bottle neck. Candidate donors who reject the ethical rules will not present themselves for donation in clinics and sperm banks. If the ethical rules remain unchanged, the medical rules that apply after the bottle neck should become less stringent if a sufficient number of donors are to be maintained. Lowering the sperm quality standards will lead to more IVF. Although this is regrettable, it will become unavoidable if the scarcity of donors increases.

Introduction

For decades, people have been complaining about the shortage of donor sperm. In general, two indications can be used to determine the existence of a shortage in a country: the presence of waiting lists and the travel of patients to another country to obtain donor sperm. A shortage is the gap between demand and supply. That implies that a shortage can be reduced or enlarged by changes on both sides. Demand for sperm can be reduced by excluding certain groups from treatment (i.e., lesbian couples) or by developing technologies that enable people to realize their wish for a child without donor sperm (i.e., ICSI). This paper focuses on changes affecting the supply side.

Ethical versus medical criteria

Sperm donors go through a selection process with multiple steps: semen analysis, family genetic history, physical examination, screening for infectious diseases, and screening for genetic diseases. This process leads to a decimation of the pool of candidate donors. An early study on donor recruitment in the United Kingdom between 1994 and 2003 showed that 3.6% of the applicants were released as donors. About 30% defaulted and 65% were rejected, mainly (85%) for suboptimal sperm quality [1]. Another study mentioned a 90.8% attrition rate between initial inquiry and completing donation [2]. A recent study from China showed that 23% of candidate donors were accepted. About 90% were rejected for suboptimal sperm quality [3]. The Chinese banks used criteria for acceptable sperm quality that were significantly higher than the WHO normal reference values. In recent years, clinics and sperm banks have also introduced expanded carrier screening to select sperm donors. This move imposes a much higher threshold on sperm (and egg) donors than on people reproducing naturally and on infertility patients using their own gametes [4]. The total risk reduction for donor offspring is less than 1% which makes it very hard to justify mandatory expanded carrier screening of donors. Moreover, the exclusion of all carriers of recessive disorders (performed by some clinics and imposed by some countries such as Denmark) would leave us with close to no donors. The higher the number of diseases screened for, the higher the percentage of donors who will be found to be carriers. A recent study showed that 17% of candidate donors were rejected based on the screening results with a panel of 47 genes [5]. Screening with a panel of 479 genes for severe monogenic diseases showed that all donors were carriers [6]. A very small risk reduction thus leads to a large drop in the number of donors. This problem could be solved by matching donors and recipients and avoid combinations in which donor and recipient are carriers of the same mutations. Still, this step further augments the cost of sperm donation and pushes people without the financial means to look for other solutions such as connection websites.

Donors are also screened on ethical criteria, e.g., criteria expressing the idea of a good donor. This selection is less visible because it takes place before men register as candidates. The main criteria are the altruistic motivation (although many donors mention a financial motive) and the anonymity/identifiability rule. Beside these criteria, multiple other aspects of the donation practice also need to be accepted by men who intend to donate. We can obtain a clearer view of the kind of rules sperm donors have to accept in the formal setting by looking at sperm donation in the informal setting of connection websites. The studies on “informal” donors reveal a large set of reasons why men prefer to donate in this setting: the possibility to select recipients, the option of contact with donor offspring, a sense of control, and a wish for more engagement [7]. These reasons deviate from the set of rules that frame the position of the donor vis-à-vis the other parties involved in the donation in the clinics and sperm banks. Men who, for whatever reason, disagree with one or more rules are unlikely to apply to become a donor in a clinic or sperm bank. Looking at the thousands of men willing to donate through connection websites, it seems that law makers and sperm banks have an interest in attracting some of these donors into the official circuit. Adapting the system to accommodate at least some wishes of these informal donors or taking away some unnecessary restrictions would be a way to accomplish this. Raising the maximum age limit may be one such restriction that may have an impact as the informal market seems to be driven by older men [8].

Numerous proposals have been made to recruit more donors by modifying the ethical rules: introducing a reciprocity system, allowing post-mortem donation, recruiting among men planning a vasectomy, and increasing payment. At the moment, very little enthusiasm is shown for such experiments even when a system (such as reciprocal donation) has proven to be effective [9]. This lack of interest and the unwillingness to modify ethical criteria creates a bottle neck in donor recruitment.

The frequently heard argument that the abolition of donor anonymity caused the shortage in sperm donors is only partially true. It is only partially true because also in countries with mandatory donor identifiability, there would be a considerably larger number of donors if all initial candidates would be accepted. To determine the effect of certain rule modifications, it is important to find out whether the change affects the inflow of candidate donors. Fewer candidate donors lead to fewer donors unless the medical criteria are relaxed. At the moment, scant data is available on how for instance the abolition of donor anonymity has affected the number of candidate donors. An example is a study in the United Kingdom that showed that inquiries from potential sperm donors went from 123 in 2000 to 18 in 2010 [10]. Given this situation, the only option left to obtain a sufficiently large donor pool is to lower the medical quality standards. Obviously, we are not suggesting to skip genetic screening through family medical history or to drop testing for sexually transmitted diseases. Our suggestion focuses mainly on sperm quality (sperm volume, progressive motility, sperm concentration, and sperm morphology) and genetic risk.

From IUI to IVF

In the United Kingdom and the United States, there has been a 300% increase in the number of IVF cycles using donor sperm between 2006 and 2016 [11]. This is remarkable since the majority of the users are lesbian couples and single women. The present situation in Australia can explain this trend. The majority of women without male partner visiting a clinic for sperm donation in Australia is treated with IVF [12]. Several factors may explain this move. Single women and lesbian couples using fertility services in clinics were on average older than women using home insemination. The success rate of IVF is higher than IUI in older women. Another factor mentioned by Power et al. is the limited supply of donor sperm. For some years now, few new donors have come forward in Australia. The limited availability explains why clinics try to use the sperm as efficiently as possible. This is done in two ways: by going directly to IVF rather than IUI since a much higher volume of semen is needed for IUI and by performing a limited number of IUI cycles (mostly 2). Only when the woman is young and assumed to be fertile and the sperm quality is high, IUI is offered by the clinics [13]. Some clinics have created two pools of donors: those whose sperm quality is sufficient for IUI and those whose sperm can only be used for IVF/ICSI. In fact, there is no solid evidence for clear lower cut-off levels of sperm parameters in IUI treatment. Ombelet and colleagues argued in their systematic review that (based on very low quality of evidence) a total motile sperm count > 1 million and a morphology > 4% could be used as cut-off levels for IUI [14]. That seems to leave a large margin for sperm banks and clinics. Sperm banks at the moment often also have different quality sperm samples at different prices for IUI and IVF. However, the requested sperm quality is still high even for the sperm samples reserved for IVF. Sperm banks have an interest in stressing the superior quality of their sperm. They frequently emphasize on their websites that only a small percentage of candidates (“only the best”) is accepted. However, at some point, being able to offer a diversified panel of donors with different characteristics may become more important for sperm banks than sperm quality. This is demonstrated in Australia where some recipients already prefer donors of the IVF pool when no donor with the desired traits is available in the IUI pool [13]. Our proposal is that lower sperm standards should be used to select donors. Donors with a higher sperm quality could still be used for IUI but candidate donors with lower sperm quality would not be lost as donors.

Lowering donor sperm criteria has been considered before and rejected because genetic perturbations in sperm may be associated with diminished semen parameters [15]. However, the assumed increase in genetic perturbations would be small for sperm samples suitable for IVF. The same discussion has been held regarding the maximum age limit of sperm donors. Studies showed that sperm quality declines and risk of genetic defects increases with higher age [16]. However, both parameters are still within an acceptable range if the age limit would be set at, for instance, 50 years. For genetic risk as well as for sperm quality, a balance will have to be found between minimizing genetic risk and retaining a sufficient number of donors. At the moment, the official system, either through law or regulation, clearly focuses on high quality and minimal genetic risk. However, the thousands of women who look for a donor online clearly show that they have a different value scale. Apart from those who are forced to avail themselves of this route because of lack of financial means, the others demonstrate that other factors (such as direct contact and being able to select the donor) besides safety and quality are important [17].

Moving from IUI to IVF has several major consequences: it adds an extra psychological and physical burden on women, it generates an additional financial cost for recipients and/or society, and it increases the risks of multiple pregnancies compared to IUI [18]. Still, a woman with a male partner with suboptimal sperm is treated with IVF/ICSI. A single woman or lesbian couple with a donor with suboptimal sperm should also be able to access IVF when no comparable donor with superior sperm quality is available. Although IUI is cost-effective in single women and lesbian couples with the current standards of sperm quality, this is unlikely if sperm quality standards are lowered or if the mean age of recipients goes up. In addition, in many IUI cycles, some form of ovarian stimulation is used thus reducing the difference with IVF. To conclude, the threshold for several parameters of sperm quality can be dropped considerable as long as there is a reasonable chance of success in an IVF cycle.

Conclusion

The increasing demand and the reducing supply will in the future generate a growing shortage of donor sperm. In the absence of miracle solutions like stem cell derived gametes, clinics, and sperm banks should start thinking of how to tackle this shortage. The bottle neck for access to donor sperm is the ethics gate. If the ethical rules remain unchanged, the medical rules that apply after the bottle neck should become less stringent to maintain a sufficient number of donors. The price to be paid for that change is the increased use of IVF. The reluctance to move from IUI to IVF is justified given the serious negative effects but the move will become unavoidable if the scarcity of donors increases.

Data availability

No data generated for this paper.

Declarations

Conflict of interest

The author declares no competing interests.