Do guys produce sperm better in warm or cold conditions

warm.

because cremaster have becomes dialleted.

Apparently, cold conditions.

Explanation:

I was curious so I went and googled it and found the following: "Sperm thrive in lower temperatures. Ideally, they should only be exposed to 4° F below body temp (roughly 94°) or cooler. This means that even small sources of heat can start to add up and damage your sperm count." Quick google search would do you the same but for the sake of it, the answer is cold conditions