The technical term is "testicular trauma". Basically, a hard thwack to the balls would do the trick. Also, a man could stop producing sperm because of a hormone imbalance, especially age related. Men never stop making spermatazoa after the onset of puberty, as long as their testicles remain intact.
NO
actively producing sperm what does that mean exactly
There is never 'NO' sperm . A lot of sperm is generated. If you lose some you gain some. The process would only stop when you are dead.
The only way to see the individual sperm is with a microscope.
The answer to your question is: No. A man can continue producing viable sperm until the day he dies. The amount can diminish if a man has recently ejaculated.
no because his sperm can't die
Had, past tense. Either it came down on it's own or with help. Either way, you only need one to produce sperm and both may be working. There may be other issues, but by itself, one undecended testicle should not stop you from producing sperm.
Other than you can get a woman pregnant, there are no real consequences to speak of. Producing sperm is a natural part of becoming a man.
The age at which a man may stop producing semen, or "cumming," varies widely among individuals. Typically, men continue to produce semen throughout their lives, although sperm production and quality may decline with age, especially after the age of 40. Factors such as health, lifestyle, and hormonal changes can also influence this process. Ultimately, there is no specific age at which all men stop producing semen.
Diabetes do not stop the sperm production normally. Uncontrolled diabetes may affect the erection in long term.
Most Men can and do produce sperm all their life, Unlike women, men produce live sperm continuously throughout their life. As they age, the ability to get an erection may impeded their ability to deliver it, and new research shows that it is not as lively & vigorous as men age, but most men produce sperm from Puberty throughout their lifetime.
In general men keep producing sperm from puberty right on until they die. As they get older the quality and quantity may decline but sperm will continue to be produced, unless they suffer damage to their testes through either disease or injury.