Fertility is the ability of humans, animals, and plants to reproduce sexually. Different methods were used to study, whether radiofrequency electromagnetic fields can lead to impaired fertility in humans and animals. Cell phone exposures were examined in most cases, but also Wi-Fi exposures. In humans, mainly male fertility (in particular the quantity and quality of sperm) was investigated. This is because of the close vicinity to the testicles of a cell phone in a trouser pocket and a laptop on the lap. This gave rise to fears that the radiofrequency fields of the devices could affect the sperm. In animal studies, offspring were investigated, especially the possible effects regarding the reproductive organs and developmental disorders. In addition to studies on humans and mammals, studies on birds and fruit flies, as well as in vitro studies directly on sperm, were also carried out.
There is no question that impairment of reproduction and development by radiofrequency electromagnetic fields may occur, when exposures are in the thermal range above the limit values and thus induce significant tissue heating above 1°C (ICNIRP 2009, p. 183, SCENIHR 2015, p. 147). Testicles, sperm, oocytes, fetuses and newborns are considered particularly sensitive to temperature.
In a review about the effects of radiofrequency electromagnetic fields on male fertility carried out on behalf of the German Federal Office for Radiation Protection (BfS), Pophof analyzed the scientific literature available and came to the following results (Pophof 2014): Six of the seven available human studies on male fertility carried out at exposures below the limits, indicate that frequent cell phone use may lead to reduced fertility. However, influencing factors which may have distorted the results were only partially or not taken into account at all. Moreover, the studies were mostly conducted on patients who had already fertility problems.
In most in vitro studies on sperm, a change due to the field influence was detected in at least one of the parameters studied, while several other parameters often remained unchanged. According to Pophof 2014, all older studies have methodological shortcomings of varying degrees. Thermal effects cannot be excluded in many of these experiments. In recent in vitro studies of a better quality, effects on sperm were shown at a SAR of 1 W/kg or more.
According to Pophof 2014, animal studies on fertility are in a large part flawed because of significant methodological weaknesses and yielded inconsistent and partially conflicting results. Studies that, according to Pophof 2014, meet the minimum requirements of scientific quality standards show no negative influence of the fields on different parameters at exposures up to 4 W/kg. However, these studies do not cover all possible parameters of fertility and thus indicate the need for further research with high-quality studies.
In their 2015 review the EU Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) came to similar results as Pophof 2014: A final evaluation of the effects on male fertility was not possible due to lack of reliable studies. It is still largely unexplored whether a pregnancy outcome will be adversely affected by expectant mothers using cell phones during pregnancy. In case of animal studies about damaging effects on sperm, replication studies with larger sample sizes were necessary. The overall conclusion is that there is strong weight of evidence against an effect of low level radiofrequency fields on reproduction or development (SCENIHR 2015, pp. 147 and 152).
Similar assessments were published by the International Commission on Non-Ionizing Radiation Protection (ICNIRP 2009) and the World Health Organization (WHO Research Agenda 2010). The many studies showing adverse effects on fertility were contradictory, had significant methodological flaws and didn't give sufficient information about methodological and technical details, such as the exact exposure strength used. ICNIRP, SCENIHR, and WHO recognize the need for further research, but not as a high priority (e.g., SCENIHR 2015, p. 221, WHO Research Agenda 2010, p. 18).
The overall result from the assessments of national and international expert committees is that no reliable conclusions can be drawn due to the many methodological shortcomings in the available studies. This means, sufficient scientific evidence is currently not available, either for or against adverse effects of radiofrequency electromagnetic fields on fertility. A new and detailed opinion from WHO regarding effects of radiofrequency electromagnetic fields is expected in 2016 (WHO Fact sheet 193).