Recently, a paper was published (Falzone et al., 2011) describing the effects of electromagnetic fields on spermatozoa parameters in samples from ejaculates of 12 volunteers. The exposure duration (1 h) as well as the intensity (SAR = 2 W/kg) are below recommended exposure limits and thus relevant to real exposure scenarios. According to the authors, temperature effects were not responsible for the effects observed, as the temperature in the exposed samples ranged between 36.8 and 37.2 °C, whereas the control samples (not exposed) were kept at 37 °C.
The effects of exposure seen with respect to morphometric assessments and acrosome status (Table 1), and sperm–oocyte interaction (Fig. 2) were quite pronounced. Immediately after exposure, and compared with the non-exposed samples, the major axis of the sperm heads was reduced on average from 5.93 to 3.53 μm (−40%), and the minor axis from 4.45 to 2.39 μm (−46%), respectively. As the volume V of a spheroid can be easily calculated (V = 0.53 × A2B, with A = minor axis and B = major axis), the reduction in volume due to exposure was very serious (from 62.2 to 10.7 μm3, approximately −83%). The volume of the human sperm nucleus alone, i.e. excluding acrosome and membranes, has been reported to be approximately 5 μm3 (Lee et al., 1997), leaving doubts about the drastic reduction in volume as reported by Falzone et al.
With regard to the above mentioned concerns, the fact that these severely shrunken spermatozoa were not different from unexposed ones with respect to viability and acrosome reaction (Fig. 1), and that they were even functional in the zona binding assay, albeit to a lesser degree (Fig. 2) therefore is incomprehensible.