Psychologically this might be a tough question, but in means of biology, what are the effects of total celibacy on the gonads and the nervous system concerning both man and woman in short and long term? Has there any research made in medical terms and as a bonus question, is there anything similar on other animal kingdom like deliberate celibacy?
Not entirely on your question but I think sufficiently relevant:
This paper (freely available) identified a non-causal link between ejaculatory frequency and incidence of prostate cancer.
Leading to results indicating that:
Giles, G.G., Severi, G., English, D.R., McCredie, M.R.E., Borland, R., Boyle, P. and Hopper, J.L. (2003), Sexual factors and prostate cancer. BJU International, 92: 211–216. doi: 10.1046/j.1464-410X.2003.04319.x
I was told in my undergraduate degree that males produce sperm all the time, and that under conditions of no sexual stimulation, that sperm is excreted involuntarily every 15-16 days, at night, while dreaming. I was also told that the renewal rate of sperm is higher under regular sexual stimulation, which increases the fertility of the sperm that is excreted.