If procreating is important to you, time to sit up and pay attention. Sperm is significantly damaged by just four hours of exposure to Wi-Fi on a laptop, according to scientists in a new study.

Tests showed that sperm were less able to swim and carried changed genetic code.

The study reads “Our data suggest that the use of a laptop computer wirelessly connected to the Internet and positioned near the male reproductive organs may decrease human sperm quality” according to ABC news.

The research was published in the journal Fertility and Sterility, and included semen samples from 29 donors who had spent four hours online. No mention was made of the websites they had to endure before depositing their sample.

The scientists say that while heat from laptops is known to damage sperm, the effects measures in this study are unrelated to the heat.

The BBC reports UK fertility expert Dr Allan Pacey, senior lecturer in andrology at the University of Sheffield, as saying: "The study is very well conducted, but we should be cautious about what it may infer about the fertility of men who regularly use laptops with wi-fi on their laps.

"Ejaculated sperm are particularly sensitive to many factors because outside the body they don't have the protection of the other cells, tissues and fluids of the body in which they are stored before ejaculation. Therefore, we cannot infer from this study that because a man might use a laptop with wi-fi on his lap for more than four hours then his sperm will necessarily be damaged and he will be less fertile.

"We need large epidemiological studies to determine this, and to my knowledge these have not yet been performed."

Pacey went on to say: "We know from other studies that the bottom of laptops can become incredibly hot and inadvertent testicular heating is a risk factor for poor sperm quality.

"There is a case report of a man who burnt his penis after using a laptop resting on his lap for a long time. Therefore, there are many reasons to try and use a laptop on a table where possible, and this may in itself ameliorate any theoretical concerns about wi-fi."

Men's Health says that by a man's 30s, there’s "a significant increased risk of sperm DNA damage leading to health problems in potential offspring".

Male health is as important in conception as female health. Avoiding alcohol, smoking and improving diet can increase chances of conception.