08:24 09 July 2009
Male fertility is plunging, with nearly one in 10 men possibly suffering - and now that scientists have created the first human sperm from stem cells, it could render men potentially useless in the future.
Ironically, the expert behind this move is a man. Professor Karim Nayernia created healthy, matured sperm by treating embryonic stem cells with acid.
The plan is to use the technique to battle infertility, such as in instances when cancer patients have been rendered sterile following chemotherapy.
Men don't have to worry too much about their futures because this sperm won't be used to create babies at this stage.
Prof Nayernia, whose team created a mouse after making mouse sperm, said of the breakthrough: "This could help us develop new ways to help couples suffering infertility so they can have a child genetically their own.
"It will also let scientists study how cells are affected by toxins.
"We can understand that some people may have concerns, but this does not mean that humans can be produced in a dish and we have no intention of doing this."
However, the good news is that male fertility is very changeable, so making positive changes to your lifestyle can have an impact on your fertility.
Listed below are some of the highlighted dangers that you might want to limit or avoid.
Fast food is often packed full of "hidden soy". Recent British research claims chemicals found in soya appear to lower sperm count and affect the ability of sperm to swim.
Sitting behind the wheel for long periods is bad for sperm. Italian researchers discovered taxi drivers, truckers and other professional drivers all had reduced fertility levels.
Additional research found that even driving for just two hours can raise testicle temperature by around 2C. Raising the temperature does affect fertility adversely.
You don't have to actually drive a car to put your fertility at risk. Scientists believe that nitrogen oxide and lead in exhaust fumes may be to blame. An Italian study of motorway tollgate employees found poorer sperm quality and less active sperm than men of the same age who were not exposed to traffic pollution.
Using a laptop regularly "may cause irreversible or partially irreversible changes in male reproductive function", according to one study. It is well known that sperm production drops if the environment within the testicles becomes too hot, which is why they are housed outside the main part of the body.
Hungarian researchers claim mobile phones could lower sperm counts by up to a third because of the radiation they emit. What's more, the ability of the sperm to swim properly could also be impaired, particularly among men who made long calls.
boys who wear disposable nappies may find it harder to produce their
own offspring when they grow up, according to German research.
Scientists at the University of Kiel found that the plastic lining
increases the temperature of the scrotum by 1C, reducing their sperm
counts as adults. They believe their discovery could explain the fall
in sperm counts over the past 25 years.
Reusable nappies had no effect on the temperature of the scrotum.
In 2001, 225 Argentinian men who had attended an infertility clinic were tested and interviewed, with a clear link found between those exposed to pesticides and very low sperm levels.
Smoking reduces the sperm count, impairs sperm movement and makes them less able to penetrate an ovum. The good news is that if you quit, the health of your sperm will start to improve within two months. Smoking also restricts the blood flow to the genitals, which contributes to a man's inability to get an erection.
Tight pants and hot tubs:
It's not a myth. Studies show that tight pants can reduce a man's chances of fathering a baby by overheating sperm-producing cells in testicles, which lowers sperm count.
Frequent use of hit tubs has the same effect.
You can't give up drinking water, but you should be aware that supplies can contain synthetic oestrogens from contraceptive pills, which are hard to break down and can adversely affect fertility.
Water companies are aware of this and are addressing the issue.
The jury's still out. Some research indicates that coffee appears to make sperm sluggish. But researchers from Brazil claim caffeine actually increases the ability of sperm to reach the egg at the right time.
Scientists from Atlanta have found that the quality of sperm starts to deteriorate as soon as men pass a healthy weight for their size. This is down to excess body fat causing localised heating in the groin area.
levels of mercury in the blood, from high seafood consumption is linked
to infertility, according to researchers from Hong Kong. The good news
for British men is that we eat less seafood than men in other
countries, and our seas have far lower levels of pollution.
Source: The Independent
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