It is has been revered throughout the ages as a mystical substance - and even written about by Aristotle. Splooge, jism, baby gravy, man milk - however you "come" to define it - semen is one of our most essential bodily fluids. And yet there's probably a lot about it you don't know - whether you produce it or just wipe it off. Read on to discover 15 bizarre facts about semen.

A study by the State University of New York found that women who were directly exposed to semen during intercourse were less depressed.

As reported by NewScientist, the study compared women whose partners wear condoms with those whose partners don't. The researchers believe mood-altering hormones in semen - including testosterone, oestrogen, follicle-stimulating hormone, luteinising hormone, prolactin and several different prostaglandins - are absorbed through the vagina. Some of these hormones have been detected in women's bloodstream hours after exposure.

"'I want to make it clear that we are not advocating that people abstain from using condoms,' says Gordon Gallup, the psychologist at the State University of New York who led the team. 'Clearly an unwanted pregnancy or a sexually transmitted disease would more than offset any advantageous psychological effects of semen.'"

A typical ejaculation (which is only one teaspoon, by the way) contains fructose sugar, water, ascorbic acid (a.k.a., vitamin C), citric acid, enzymes, protein, phosphate and bicarbonate buffers, and zinc - but only about 5 calories.

Nutritional value per serving:

150 mg. protien
11 mg. carbohydrates
6 mg. fat.
3 mg. cholesterol
7% US RDA potassium
3% US RDA copper
3% US RDA zinc

According to Askmen.com, fellatio may make pregnancy safer. Women who engage in oral sex before getting pregnant are at less risk for blood pressure problems during their terms than those who don't. The reason for this is that regular exposure to semen before pregnancy helps a woman's immune system get used to her partner's sperm. (and that's assuming she's having oral sex with the guy who's getting her pregnant).

Traditional Chinese medicine and the practice of Chi Kung (Qigong) place huge emphasis on a form of energy called "jing" meaning "essence" or "spirit" which one should try to develop and accumulate. Jing is also sexual energy and is considered to dissipate with ejaculation, making masturbation "Energy Suicide" amongst those who practice the art of Chi Kung.

According to Chi Kung theory, energy from many pathways or meridians in the body becomes diverted and transfers itself to the sexual organs during sexual excitement. Orgasm and ejaculation finally expel the energy from the system completely.

In some cultures, semen is attributed with special properties of masculinity. Among the Etoro people of Papua New Guinea, it is believed that young boys must fellate their elders and ingest their sperm to achieve proper sexual maturation. I'm not sure that would "go down well" at most bar mitzvahs.

Most semen is basically white, but grey or even yellowish semen can be normal as well. Blood in the semen can cause a pink or reddish color and may indicate a medical problem which should be evaluated by a doctor.

8. It's designed for a hostile environment

Semen is designed to protect sperm in the very acidic vaginal environment, which is viscous and patrolled by immune cells. The basic alkaline components of seminal plasma counteract the acids and protect the DNA inside the sperm from acidic denaturation.

7. A cast of millions

About.com reports that one spurt of ejaculate can contain anywhere from 40 million to 600 million sperm cells depending on the total volume and the length of time the semen has been stored before ejaculating. Yet, the quantity of sperm produced will still only cover the head of a pin.

Some people believe the bitter or salty taste of semen can be changed depending on what you eat, although there have been no scientific tests to back this up (and I'm not going to volunteer).

One theory is that fresh fruit like pineapple, melon and mango, leafy green vegetables or even cinnamon can make semen taste sweeter. Coffee, smoking and excessive red meat or dairy are supposed to make it taste bad.

Swimming (live) sperm can survive in the vagina from three to 24 hours, and up to seven days in the cervix. And you might be surprised to learn (as I was) that sperm can survive for six to 13 hours in the mouth. Forensic scientists say non-swimming sperm can be found in the vagina from 14 hours to 17 days, and in the cervix for up to 12 days.

4. Tight underwear is not your problem

Many men believe that tight underwear lowers their sperm count. In truth, there is really only a slight difference in temperature in tight underwear, which should not affect sperm production. By the way, the entire production of sperm formation to maturation takes about 72 days. Every day an adult male produces several million sperm cells.

According to SpermAccount.com, sperm cannot survive freezing without adding some agents that prevent the cells from rupturing during freezing and thawing.

"These agents are called "cryoprotectants" and are usually composed of egg yolk, glycerol and some buffers. The cryoprotectant is slowly added to the fresh ejaculate, and the sperm is gradually cooled and then frozen in liquid nitrogen at a temperature of -195 degrees centigrade."

It is normal for about half of the sperm cells to die during the freezing and thawing process. "Robust" sperm can usually survive several years when frozen.

After ejaculation, semen first gets a little thicker through a clotting process and then becomes more liquid. It is believed the initial clotting helps keep the semen in the vaginal canal, but then the change to a more liquid state frees the sperm to make their championship swim to the egg. Immediately after ejaculation, semen is typically a sticky, jelly-like liquid often forming globules (a string of pearls!) but within 5 to 40 minutes it becomes more watery and liquid before finally drying (on navy blue dresses and other artifacts).

1. Masturbating won't make you run out of semen

Unlike petroleum, semen is a fully renewable resource. When a man ejaculates semen, his body simply makes more. It's very similar to the way your body makes more saliva after you spit - or more mucus after you sneeze.

For those guys out their using the, "I will EXPLODE if you don't have sex with me and my death will be on your shoulders!" line on their wives and girlfriends, I suggest trying another, more honest, approach. Better yet, try flowers. According to TheSite.org, there is no need to have sex or masturbate to ejaculation for health reasons. The body can happily cope with unused sperm, with no impact on or sex drive.

Then again, according to an article in NewScientist, a US study, which followed roughly 30,000 men over eight years, "showed that those who ejaculated most frequently were significantly less likely to get prostate cancer." The results backed an Australian study that masturbation was good for men.

Need more information before sending this along to your wife or girlfriend?

"Increased ejaculation may allow the prostate gland to clear itself of carcinogens or of materials that form a substrate for the development of carcinogens," explains Graham Giles, who led the Australian study. "Another theory is that frequent drainage of prostate fluid stops tiny crystalloid microcalcifications - which have been associated with prostate cancer - from forming in the prostate duct."