Is masturbating healthy for a person? What have scientific studies shown? Smoking is pleasurable, but is bad for a persons health. What are the affects of masturbation on a persons mental and physical health?
The problem with legitimate studies on masturbation is that the subjects typically end up double-blind. 
I thought it was because they had so much trouble getting a control group.
Personally, I think horniness leads young men at least to indulge in too much irrational, stupid, and downright dangerous behaviour, so in that sense masturbation is healthy.
Only young men masturbate?
Regular orgasms have been shown to have a positive effect on health. Sex’ll get you there with some more physical exertion, which barring any medical problems is healthier for you, but masturbation certainly isn’t bad for you.
Personally, I think it’s healthy not only for the practitioner (just think how much lower his/her stress level is, and let’s not forget that women masturbate too, and we all know the health benefits of low stress levels!), but for significant others, too.
Just think how often there’s an imbalance of libidos in a relationship: if it weren’t for masturbation, and the hornier partner had to nag the less libidinous one until he/she finally gave up in order to get any release, there’s be a lot more black eyes out there.
In this column, Straight Dope Staff Jill says that all of the reported health dangers of masturbation are myth.
I didn’t say that only young men masturbate, but I was only addressing that particular portion of the masturbatory population, because I have some experience in that area, having once been a young man. Now I’m an old man.
Whew. I hope that clears that up. It was not my intention to slight any women, young or old, in my previous post.
What about chafing. That can be a problem I am told.
Has anyone masterbated with any thought as to whether it was healthy or not?
Never crossed my mind. 
Your body can only produce sperm so quickly, so excessive masturbation can cause you to have a low sperm count until your testicles catch up. Not a problem unless you’re trying to get someone pregnant, and if you are masturbation probably isn’t a big issue for you.
There is the chafing issue, especually if you’re uncircumsized. That’s what lube is for.
Oh, and there’s this: http://www.dbaseiv.net/
[hijack]What if you don’t masturbateor have sex? Are you risking your health?
I read somewhere and if I can find a link to it, I’ll show it that lesbians had an easier time during menopause with feminine dryness because of the supposed frequency of masturbation.
http://www.contemporaryobgyn.net/hostedfiles/features/atrophicvaginitis_partone/07.htm
I definitely don’t want to know what the placebo would be in the OP’s study.
Aren’t regular orgasms good for keeping the prostate healthy? I read that somewhere.
Eva Luna, your point is a strong one which has made me not need to post. Although it wears thin, it has spared my relationship much stress
Speaking strictly of men (yes, we all know women do it too;)), I think I once read some place that masturbating changes the male hormone testosterone into a less “dangerous” form so that the male is less likely to get testicular cancer. That actually brings up a good question. Is it unhealthy not to masturbate? My advice: play it on the safe side and just continue doing it;).
How about the mental effects? I’m curious about that. I’ve got this, erm, friend you see… ahem 
This cite has alot of interesting info about it.
Consult this thread.