Male Infertility and Testicular Heat

Man in white shirt and underwear with hand on hip

You probably heard it at some point in your life – stay away from those “tighty whiteys.” It may seem like a trivial piece of advice that was never fully explained to you as a child or young adult. However, it is a warning rooted in excellent science and can make a difference in a man’s fertility.

To understand precisely how the proper function of the testicles makes a difference in male fertility, we need to understand more about the anatomy. There is a good reason why the testicles hang outside of the body exactly the way they do – for temperature regulation. Sperm production and quality are most efficient at several degrees below average body temperature – around 93 degrees Fahrenheit.

The automatic relaxation and contraction of scrotal muscles, known as the cremaster muscles, achieve this. If you’ve wondered why the scrotal sac retracts significantly in the cold, the body is attempting to maintain average testicular temperature by moving them closer to the warmer body. Similarly, in hot environments, the cremaster muscles relax, moving the testicles further away from the body, and allowing them to cool. It’s a deliberate and coordinated process that assists with fertility.

Is This a Common Cause of Infertility?

The type of underwear you use is likely a very small part of any potential infertility issue. However, we caution men to avoid daily hot tubs and saunas, excessively hot baths, and anything that alters the heat balance in the scrotum. Some detrimental effects of testicular heat imbalance include1:

  • A decrease in motility and mass motility of ejaculated sperm
  • More sperm showing defects
  • Damaged plasma and acrosome membranes
  • A decrease in sperm with high mitochondrial membrane potential

This may be discussed when you visit Dr. Kapadia with concerns about infertility.

Scrotal Botox (Scrotox)

In a similar fashion to vaginal rejuvenation on the female side, some men believe they need cosmetic improvements to their private parts. They often achieve this by using Botox or botulinum toxin injections in the scrotal muscles to smooth the sac and improve its appearance. For the reasons mentioned above, changing the muscular performance of the scrotum can cause fertility concerns. Issues associated with the continued function of the scrotum musculature may also occur due to these injections. As such, we do not suggest that this be part of any man’s sexual health plan.

The Bottom Line

It is evident that the body maintains a very delicate balance to ensure proper overall function. The testicles and scrotum are no exception. If you experience any possible fertility issues and have not been able to conceive with your partner for a year or more, visit Dr. Kapadia to understand more about potential causes and solutions.


  1. Hamilton TR, Mendes CM, de Castro LS, de Assis PM, Siqueira AF, Delgado Jde C, Goissis MD, Muiño-Blanco T, Cebrián-Pérez JÁ, Nichi M, Visintin JA, Assumpção ME. Evaluation of Lasting Effects of Heat Stress on Sperm Profile and Oxidative Status of Ram Semen and Epididymal Sperm. Oxid Med Cell Longev. 2016;2016:1687657. doi: 10.1155/2016/1687657. Epub 2016 Jan 17. PMID: 26881013; PMCID: PMC4737001.