Semen facts

Want to know more about the stuff that sticks your sheets together and creates new life? Here’s everything you need to know about sperm and semen.


"Meet you at the starting line, Spermy."

How are sperm produced?

  • Sperm are produced in the testes, where it takes approximately 10 weeks for a single soldier to reach maturity
  • Every day, a healthy adult male can produce around 70 to 150 million sperm
  • They are only 55 millionths of a millimeter (or 55 microns) in length
  • Matured sperm is stored in the epididymis – the coil like structure that runs across the top of each testicle
  • Sperm can remain in the epididymis for about two weeks before being delivered up as ejaculate, or broken down and reabsorbed by the body

What does semen contain?

Semen doesn’t just contain sperm, but fluids secreted by several glands during ejaculation.

When you get a hard on (and close to the point of climax) semen travels through a tube called the vas deferens and picks up a sugary substance that acts a bit like rocket fuel. Other fluids are added along the way to the urethra (the tube that runs the length of the penis).

The finished product contains approximately just 10% sperm. The rest consists of enzymes, vitamin C, calcium, protein, sodium, zinc, citric acid and fructose sugar.

How much semen comes out when you ejaculate?

You may think it’s enough to fill a pint glass, but the average amount is half a teaspoon. This could contain anything between 40 to 250 million of the little wrigglers.

What’s a ‘normal’ sperm count?

There can be a massive variation in your sperm count; factors such as stress and obesity can make a huge difference. But according to The World Health Organisation, a normal sperm count should:

  • have a concentration of at least 20 million sperm per ml
  • be at least 2ml in volume
  • contain at least 40 million sperm in the ejaculate
  • contain at least 75% live sperm (it’s normal for up to 25 per cent to be dead); of these at least 30% should be of normal shape and form
  • be swimming with rapid forward movement (at least 25%)
  • be swimming forward, even if only sluggishly (at least 50%)

How does sperm fertilize an egg?

Once you’ve ejaculated, your sperm goes on an epic quest to find the egg. First they have to survive the acid in a woman’s vagina, which can be deadly to sperm, and swim through cervical mucus, which can feel like swimming through treacle. Then they have to travel about seven inches up the fallopian tube (they travel roughly an inch every 15 minutes, so that’s quite a schlep).

A healthy sperm that swims in a fairly straight line can make it in 45 minutes, whereas it may take a straggler up to 12 hours. Only a dozen or so make it to the egg; the others die en route, get lost or trapped. The survivors work frantically to penetrate the egg, but it only takes one to fertilise it.

What happens to sperm if I don’t have sex or masturbate?

The body can happily cope with unused sperm, with no impact on fertility or sex drive. If it doesn’t come out in a wet dream the body will absorb what it doesn’t use or need.

Can you improve the quality of your sperm?

From eating certain foods to keeping your balls cool, there are things that you can do to improve the quality – and taste – of your sperm.

If you want to give the little fellas a turbo boost, add the following to your diet: fruit, fish oils, walnuts, edamame beans (in fact, beans of any description), avocado, asparagus, lean beef, dark chocolate, garlic and pomegranate.

If you want sweet-tasting sperm eating a diet rich in yellow/orange fruits – like pineapple and mango – is said to help. Add to that some leafy green veg, parsley, celery and cinnamon and you’ll have Michelin-starred sperm.

Sperm also like to be cold – which is why your balls are on the outside of your body and why hot baths, saunas and hot tubs can temporarily reduce your fertility (contraception is still the only way to avoid getting a girl pregnant, mind).

What’s not so good for sperm

In terms of diet, too much saturated fat (burgers, chips, too much dairy, fatty meat, sausages and bacon, pies, cakes biscuits etc) may slow up production.

As for lifestyle, smoking (cigarettes and weed), alcohol and too much coffee are also thought to affect taste, as does your state of health. Smoking weed is also said to lower sperm count.

Help, my semen is lumpy

Semen consistency varies from day to day, but can become thick or lumpy if you’ve been unwell or feeling a bit peaky. It has no impact on fertility, however, but if you’re experiencing any pain or discharge (or you’re concerned in any way) then don’t hesitate to check it out with your GP to check for any underlying medical problem.

Photo of sperm by Shutterstock

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Updated on 29-Sep-2015