As a result, our knowledge on the little swimmers is seriously lacking.
How long can sperm live? What affects a man's sperm count? And why does semen have that distinct smell?
We asked Dr Nitin Shori, Medical Director of the Pharmacy2U Online Doctor some quick questions about sperm and Dr Geeta Nargund for the low down on male fertility.
Facts from Dr Nitin Shori:
1. How far can sperm swim?
Once ejaculated sperm only have to swim about 18cm from the cervix to the fallopian tubes, where they hope to find an egg to fertilise.
With tadpole-like tails, they are designed to swim forwards proficiently and find their way through the wilderness. But just like their human counterparts, some appear to have a better sense of direction than others
This intrepid journey is quite a feat for the micro swimmers, who aren’t even visible to the human eye.
2. What is sperm actually made out of?
Sperm carry half the DNA package needed to create a baby. However, these miniature baby-makers only make up around 3-4% of the seminal fluid released during ejaculation. The rest consists of sugars and mucus.
3. How much sperm does a man produce in his lifetime?
Each drop of semen usually contains millions of individual sperm, but its potency can vary significantly from man to man.
In theory though, a man could produce trillions of sperm in a lifetime.
4. What makes semen have a distinct smell?
Semen can tend to smell a bit like chlorine. It shouldn’t be foul smelling though, as this could be a sign of an infection. Its colour could also be an indication of a problem, so keep an eye out for any yellow or green tinged semen, or other changes that seem unusual.
5. How long can sperm live for?
Once outside the body, the sperm have a very short lifespan and will die by the time the semen has dried. However, a determined sperm can survive for up to a week in a female’s fallopian tubes, while waiting for an egg to fertilise.
While there are plenty of "fun facts" when it comes to semen, sperm becomes serious business when a couple are trying to have a baby.
We asked Dr Geeta Nargund, medical director of CREATE Fertility, some key questions about male fertility.
1. How common is male infertility?
For couples with infertility problems, male infertility is a contributing factor in up to 50% of cases. It is the sole cause in about 30% of cases.
2. What should sperm count be in order to be "healthy"?
15 million per ml or more is considered to be a normal sperm count. However, it’s not just the number which is important - you also have to assess quality indicators such as motility (speed of movement) and morphology (normal shapes).
The normal sperm parameters are:
Sperm Count: 15 million per ml or more
Progressive motility: 32% or more
Morphology: 4% or more
As you can see, men can have up to 96% abnormal shaped sperm and it is still considered to be a normal sperm sample, as long as other parameters are within the normal range.
3. When does sperm count start to cause fertility problems?
When the sperm sample does not meet the normal parameters above, it is likely to cause fertility problems. However, having sperm sub-optimal sperm parameters does not always mean that they are not able to father a child.
It often means that the chances of naturally conceiving are reduced, rather than eliminated.
4. Is fertility something men worry about?
Not always because they tend not to be aware of how up to half of infertility problems could be due to sperm problems.
If awareness of the issues around infertility were better known, I think men would be more proactive about understanding and improving their fertility.
I believe that it is as important as raising awareness around female fertility and helping women to improve their fertility.
5. Do you think men are less inclined to talk about fertility issues than women?
In my experience, yes, compared to women, men are less likely to talk about fertility problems with family and friends.
Women tend to share and talk with each other about fertility problem as “getting pregnant” seems to be considered a female issue. In reality, men want to be fathers as much as women want to be mothers, but it’s not a topic they want to bring up in pubs or offices.
6. What can people do to naturally up their sperm count?
Men produce brand new sperm every two to three months. Their lifestyle in the preceding months is incredibly important in determining the quality of their sperm.
Lifestyle issues include alcohol intake, smoking, taking recreational drugs, which all negatively affect sperm function. Stopping smoking and recreational drug-use is an obvious first step.
As regards to alcohol intake, there are no quantitative studies, but we advise to reduce alcohol intake and to not drink more than 8 units in 48 hours - no binge drinking!
Stress can have a negative impact on sperm quality. It is important that men reduce their levels.
The other factors include anything that contributes to an intermittent increase in scrotal temperature. This means things such as taking hot baths, sitting at a desk or on a sofa for long periods of time and long distance driving without taking a break.
Of course, sperm problems are not always down to lifestyle issues. There are sometimes underlying genetic and medical causes. These can include problems such as undescended testes, testicular infections or inflammations, mumps during adolescence, and chromosomal problems.
7. Where can men seek help if they are worried about their sperm count?
The first step should be to seek advice from their GP. If they are concerned or worried, they can have a sperm test at a fertility clinic and get further advice.
We run free Open Days where men can get more information and advice.