Testosterone is an androgen. It is responsible for the development and maintenance of male characteristics. But, testosterone effects more than just muscle mass! Testosterone is responsible for:

• Fertility and libido
• Development of masculine characteristics
• Bone density, muscle mass, and body fat composition
• Heart health, red blood cell production, energy, and vitality
• Confidence, emotional well-being
• Mental focus and social intelligence
• Prevents development of female characteristics

Yes, keeping your testicles cool is critical for keeping them healthy, but this does not mean that icing them is a good idea. The point is simple:

• You don't want to over-heat your testicles.
• But, you also don't want to over-cool your testicles.

Over-testicular hypothermia is associated with a whole set of negative symptoms as well. So--normalizing testicular temperature is key.

On the other hand, short-duration (10-30 second) cooling treatments are actually beneficial, especially to overcome heat-stress. This is because the modern lifestyle is heat-toxifying, and also that cooling has inflammatory effects, and also promotes healthy vascular function. 

Guys, if you wear the wrong underwear, you can end up making your varicocele bigger, and damaging your testicles.