FLR101 Chapter 1-1: Health concerns about semen retention

I received this question from a reader recently:

Great blog full of practical information, thank you!

Given your medical/science background, do you have any health concerns regarding long-term retention? My wife's previous schedule was a monthly ejaculation. We are gradually working on increasing the length between ejaculations to once or twice a year which I am in complete agreement with.

Are you aware of any health risks with such a long term schedule? I'm currently at almost three months and feel great so far. Thank you for your consideration.

 I answered it in the comments section, but I thought it would be worth going into it with a little more detail.  There really isn't any consensus on this in the medical community, but there are some interesting studies to look at.  However, different studies reach different conclusions which may just add to the confusion more than clarification on the issue.

Polyxeni Dimitropoulou, PhD; Rosalind Eeles, PhD, FRCP; and Kenneth R. Muir, PhD, obtained detailed sexual histories from 840 men. About half the men developed prostate cancer by age 60, and about half did not have cancer.

This was a 2009 study that states frequent masturbation for men is 2-7 times a week for men in their 20-30s and increased the risk of prostate cancer compared to same age men masturbating less than once a month.  These frequent masturbators had a 79% greater chance of prostate cancer by age 60.

For men in their 50s, frequent masturbation was defined as one or more times per week compared to same age men that reported never masturbating.  These 50 year old masturbators had a 70% less chance of prostate cancer.…