Underwear, Sperm Quality, and Fertility Wishes - What's the Truth Behind It?
Numerous media outlets have reported in recent years on a decline in sperm count by up to 50% since the 1970s. Various environmental factors are discussed as possible causes, including pesticide residues, endocrine disruptors from plasticizers, and drug residues in drinking water. A potential additional influencing factor, which in our opinion receives too little attention, is the warming of the testicles and epididymis, which could impair sperm production.
At the same time, many couples in Germany remain involuntarily childless. Various studies show that the cause of involuntary childlessness lies with the man in approximately 40-50% of cases.
Heat Stress and Spermatogenesis
To understand the influence of temperature on sperm quality, one only needs to look at male genital anatomy. In humans, the testicles hang outside the core body in a scrotal sac, where the temperature is lower than the core body temperature. Thermoregulation essentially occurs via the distance to the core body and heat dissipation through the surface of the scrotum. Additionally, the arterial blood flowing into the scrotum is guided through a venous countercurrent system and thus somewhat cooled. This is because spermatogenesis requires a slightly lower temperature than the core body temperature. Numerous studies investigate a connection between testicular warming and reduced sperm count and/or quality.
Influence of Underwear on Sperm Count and Quality
In connection with the topic of sperm count and quality, a possible correlation with the type of underwear men wear has also been investigated. While there is no definitive evidence, some studies suggest a plausible connection. For example, a Harvard study (Mínguez-Alarcón et al., 2018) found that men who regularly wore boxer shorts (meaning normal loose boxer shorts) had a 25% higher sperm concentration and a 33% higher total number of motile sperm than men who wore tight-fitting underwear. Abdelhamid et al. 2019 found in a study that a slight, artificially induced temperature increase of the testicles and epididymis by 1.5-2°C can impair sperm morphology. To achieve the temperature increase, specially designed underwear was used, which kept the testicles in a supra-scrotal position. The authors concluded that in the context of fertility investigations, the topic of occupational and environmental temperature increases of the testicles and epididymis should be considered, and that doctors should advise their patients to avoid any risk of temperature increase. Additionally, Abdelhamid et al. 2019 mention the reversibility of the observed effects and suggest using the effect as an alternative method of male contraception. The topic of thermal contraception for men has already been taken up by several authors. A well-founded review on the subject is provided by Soufir 2017.
However, it is important to note that scientific studies can have weaknesses and a general transferability to the general public is not necessarily given. There are also dissenting voices that see no connection between underwear and sperm count and/or quality or criticize corresponding studies. The transferability of the observed effects to everyday life and the role of outerwear (e.g., tight-fitting jeans) is therefore controversially discussed in the scientific community.
From a physical perspective, it seems plausible to us that tight-fitting underwear, which lifts the testicles and thus brings them closer to the body or even presses them against it, could lead to a temperature increase. With loose boxer shorts, the genitals can hang freely, so that the natural anatomical distance and the associated thermoregulation remain physiologically preserved. Ultimately, the body represents a heat source. With a shorter distance of the testicles to the core body, a temperature increase can accordingly occur due to stronger heat radiation and heat conduction. In addition, a change in position and a possible compression of the scrotum could potentially physically influence further cooling mechanisms (surface of the scrotum, countercurrent principle of afferent and efferent blood vessels) of the testicles and/or epididymis.
Fertility Wishes and Underwear - What Makes Sense?
Regardless of the inconclusive clarification of how strong the influence of underwear on sperm count and quality actually is, it seems at least plausible that tight underwear, which lifts the testicles and thus brings them closer to the body than is physiologically normal (or even presses the testicles against the body), could contribute to a temperature increase. In view of numerous studies on testicular temperature and sperm count, we consider a negative influence on sperm count and quality to be plausible, and this is also explicitly supported by the approach of a functioning contraceptive method that precisely utilizes this principle.
Against this background, we believe that the topic of underwear in relation to men wishing to have children may be neglected, but a public discourse is largely absent. In our opinion, the goal in this context should always be to avoid overheating of the testicles, therefore some leisure activities or habits (e.g., heated seats) should also be critically questioned with regard to this topic. Finally, we may even see a need for action on the part of various regulatory authorities here.
What does MANDERWEAR have to do with this?
As a manufacturer of high-quality men's underwear, we feel obliged to take this issue into account and therefore question classic designs and cuts of tight-fitting men's underwear not only because of wearing comfort, but also with regard to male fertility. Therefore, in the course of product development, scientific considerations on testicular temperature were also taken into account, although there are no reliable clinical studies on our product to date. Our design, in addition to focusing on the best possible wearing comfort, also aims to consider aspects that could be associated with a more favorable testicular temperature from a scientific point of view. Thus, our underwear is tight-fitting, but the genitals (and thus also the scrotum) can hang freely, without any supporting or holding function. The pouch is deliberately made in a single layer. Furthermore, we naturally rely on breathable materials such as viscose or modal, each in combination with elastane.
Our men's underwear was developed taking into account anatomical and physical aspects to promote the most natural testicular position possible (free hanging without any supporting or holding function, no constriction). Whether and to what extent this has a measurable influence on sperm count and/or quality has not yet been proven by clinical studies. We are therefore looking for institutional cooperation partners in this area.
If you, as a man wishing to have children, choose our products, we are very pleased. You will receive a highly functional, innovative premium product with a very high wearing comfort.
We are interested in collaborations in reproductive medicine and andrology
For the reasons mentioned above, as a manufacturer of innovative and scientifically sound men's underwear, we are fundamentally interested in collaborations in the field of reproductive medicine, sperm quality depending on the men's underwear worn. We therefore welcome institutions and/or practices in urology, andrology and reproductive medicine as well as manufacturers of medical devices or related fields with an interest in corresponding studies. Collaboration with institutional investors is also desired. Please also note our comprehensive intellectual property portfolio (German and European patent applications, registered design, registered trademark). Please contact us by email at info@manderwear.de or via our contact form.
Author: Alexis Knell. This article was written with the support of AI and subsequently reviewed and edited by the author.
Transparency Notice:
We would like to point out that this article was written by us as a manufacturer of innovative men's underwear. We hereby disclose that we have a commercial interest in the topic. We do not have our own scientific studies on the effects of our products on testicular temperature or fertility. Statements about possible physiological effects are based on generally accessible specialist literature and physical considerations. This article does not constitute medical advice and does not replace consultation with doctors.
Sources:
- Mínguez-Alarcón, L., Gaskins, A. J., Chiu, Y.-H., Messerlian, C., Williams, P. L., Ford, J. B., Souter, I., Hauser, R., & Chavarro, J. E. (2018). Type of underwear worn and markers of testicular function among men attending a fertility center. Human Reproduction, 33(9), 1749–1756. https://doi.org/10.1093/humrep/dey259
- Abdelhamid, M. H. M., Walschaerts, M., Ahmad, G., Mieusset, R., Bujan, L., & Hamdi, S. (2019). Mild experimental increase in testis and epididymis temperature in men: Effects on sperm morphology according to spermatogenesis stages. Translational Andrology and Urology, 8(6), 651–665. https://doi.org/10.21037/tau.2019.11.18
- Soufir, J.-C. (2017). Hormonal, chemical and thermal inhibition of spermatogenesis: Contribution of French teams to international data with the aim of developing male contraception in France. Basic and Clinical Andrology, 27(3). https://doi.org/10.1186/s12610-016-0034-2