Sat-10 Mar-2012, Dear Respected Doctor I am asking you a question for the first time and your quick response will be highly appreciated. Dear Doctor I am 36 years old married healthy man , I have two questions to be asked Q-1: What is the effect of tight underwear or pants on sperm production & sperm motility? I read contradictory statements of doctors regarding the effect of tight underpants on sperm production & motility. Q-2: My friends told me that wearing underwear is must for a male, as not wearing underwear may hurt ones testicles or testicles may get twisted. While surfing the net I found that some tribes in South AAAAAAA or Brazil are always fully nude, and perform all their daily routines like running , swimming , climbing trees & hunting without any support for their testicles. Even vanuhatu tribes were doing bungee jumping fully nude almost from a height of 80 feet (as shown in a YouTube video). Now the question arises that if support is necessary for the testicles then why these tribam men (as mentioned above) do not get their testicles hurt/injured or twisted? I asked my friends but they could not answer it. Now I hope to get some correct medical view from your side, please I am really confused!! Thanking you Mr . AAAAAAA AAAAAAA (India)