In September 2018 researchers from the USA published the results of their study to assess whether types of underwear could increase scrotal temperature. It is already known that elevated scrotal temperatures can adversely affect testicular function, but findings as to whether types of underwear can cause an increase in scrotal temperature have been inconsistent. A total of 656 male partners (aged 32-39 years) of couples seeking infertility treatment were included in the study. Information on type of underwear worn was collected via questionnaire and it was seen that 345 men (53%) usually wore boxers. Semen samples were collected and analysed. Results showed that men who reported usually wearing boxers had a 25% higher sperm concentration, 17% higher sperm count and 14% lower serum FSH levels than men who did not. However, the researchers urged caution as other modifiable life styles could also potentially alter scrotal temperature (eg types of trousers, textile fabric of the underwear)and may be confounding factors.
Mínguez-Alarcón L et al. Type of underwear worn and markers of testicular function among men attending a fertility center. Hum Reprod. 2018 Sep 1;33(9):1749-1756