Effects of virtual reality erotica on ejaculate quality of sperm donors: a balanced and randomized controlled cross-over within-subjects trial

Abstract

Background: Previous research has shown that the type and duration of erotic material that men have access to during masturbation can influence semen parameters. To our knowledge, the use of virtual reality (VR) headsets to present erotica has not previously been studied. We reasoned that, because VR can provide a more immersive experience to the user, semen parameters of masturbatory ejaculates may be altered.

Methods: This study had a balanced and randomized controlled cross-over within-subjects design. 504 ejaculates were collected from 63 sperm donors at 4 locations in Denmark. During masturbation each donor was instructed to observe erotic material either on a touch screen monitor or using a VR headset. The order of each pair of within-subject treatments was randomized by the throw of a dice. Anonymized data were analysed with linear mixed and piecewise structural equation models.

Results: Both abstinence period and VR-use influenced the total number of motile spermatozoa ejaculated. For short abstinence periods, VR-use increased the number of motile sperm in the ejaculate. However, the difference between VR and non-VR ejaculates decreased as abstinence period increased such that there was no difference at the mean abstinence period of 58 h. For longer abstinence periods, total motile sperm counts were lower, on average, when men used VR compared to those that did not.

Conclusion: The use of VR headsets to view erotica had a strong positive effect on the number of motile sperm in an ejaculate when the donor's abstinence time was short (< 24 h). VR-use could improve the ejaculate quality of men who are asked to provide samples after a short period of abstinence, such as men in infertile partnerships producing samples for ART or cancer patients depositing sperm before treatment.

Trial registration: Trial retrospectively registered on 13 July 2022 at ClinicalTrials.gov. Identifier: NCT05457764.

Keywords: Ejaculate quality; Erotic stimulation; Male fertility; Sperm donation; Virtual reality.

Fig. 1

Effect of abstinence period on total motile sperm count (TMSC), with and without using VR. (A) interaction plot from the full model (Table 1) with 95% confidence limits on each predicted regression. (B, C) Separate predicted regressions from models for donors with and without VR, with symbols showing the raw data. Note the log scales on all graphs

Fig. 2

Effect of VR use on (A) the donation period and (B) ejaculate volume for each donor during each sperm donation (red, 252 donations in each category) and for the averages of all donations made by each donor (grey; 63 means in each category). Black symbols are means ± 95%CLs. Note the log scales on both graphs

Fig. 3

Path diagram from piecewise structural equation model showing the relative magnitude of effects; estimates on each arrow are standardized coefficients such that they are on the same scale and directly comparable. Green arrows are significant effects whereas grey arrows are not significant. The width of each arrow also indicates the magnitude of each effect. Arrows join variables that might plausibly influence one another and thus directly or indirectly have an effect on the total motile sperm count (TMSC).