Scientists studying mice have identified a gene which could boost human fertility.
Experts say the discovery, announced in a journal today, could help people struggling to conceive naturally.
A Durham University team working with scientists from Osaka University in Japan were studying fertility in mice when they discovered that the gene, which makes a protein called PDILT, enables sperm to bind to an egg, a process essential to fertilisation.
They found that when the gene was switched off in male mice, less than 3% of females' eggs were fertilised compared to more than 80% in mice when the gene was left switched on.
It is the first time that a gene of this type has been linked to fertility.
Adam Benham, of Durham University's school of biological and biomedical sciences, said: "The protein is an essential part of the navigation system of sperm.
"It helps sperm swim through the oviduct to the egg and without it sperm get stuck.
"Our results show that navigating the oviduct is an important part of the fertilisation process.
"Like any navigation system, you have to programme where it is that you want to go and this protein plays an essential role in getting sperm to the right destination, in good shape, and in good time."
The researchers also found that the cumulus cells, a cluster of cells surrounding and protecting an egg, play an important role in fertility - their presence enables sperm to bind properly to an egg.
Although the research and findings are at an early stage, the researchers now hope to look at how the gene affects sperm-to-egg binding in humans.
The findings are published in the journal PNAS, Proceedings of the National Academy of Sciences.
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Open Image ModalPlus fertility-boosting food you should be eating..
Fertility-Boosting Foods
Natural Ways To Boost Your Fertility(01 of09)
Open Image Modal (credit:Alamy)
Avoid White Bread, Pasta & Rice(02 of09)
Open Image ModalAlthough there is no direct link between refined carbohydrates and infertility, the refining process strips grains of some of the most important fertility-boosting nutrients, such as antioxidants, B vitamins and iron. (credit:Alamy)
Go Organic(03 of09)
Open Image ModalModern methods of food production, involving intensive farming, rob the soil of vital nutrients, so where possible stick to organic produce. Processed foods are packed with additives and preservatives that can upset blood sugar levels and disrupt the body's hormonal balance. (credit:Alamy)
Cut Down On Red Meat(04 of09)
Open Image ModalToo much red meat increases the amount of ammonia in the body, which can interfere with the implantation of the egg in the uterus. Red meat can also be detrimental for men as it increases acidity and affects sperm activity; sperm perform better in alkaline conditions. (credit:Alamy)
Switch To Soya Milk(05 of09)
Open Image ModalThe animal hormones in dairy products can affect your own hormonal balance. If you balk at the richness of soya milk and can't bear to give up your semi-skimmed, switch to organic dairy products instead as these contain lower levels of hormones. (credit:Alamy)
Reduce Your Alcohol Intake(06 of09)
Open Image ModalCurb Caffeine(07 of09)
Open Image ModalWhile you don't need to give up your morning coffee, caffeine does constrict the blood vessels, slowing blood flow to the uterus and potentially making it harder for an egg to grab hold. So, if you're having any trouble conceiving, or undergoing IVF treatment, you might want to go easy on the double espressos. (credit:Alamy)
Get Your Five-A-Day(08 of09)
Open Image ModalAside from being packed with vitamins and minerals, fruit and vegetables are packed with antioxidants that attack free-radicals (harmful molecules that can damage the ova, sperm and reproductive organs). (credit:Alamy)
Fertility-Friendly Vitamins(09 of09)
Open Image ModalZinc helps to maintain a healthy menstrual cycle as well as being vital during pregnancy to aid cell division in a developing foetus. Folic acid (Vitamin B6), together with zinc, is essential in the function of female sex hormones. Vitamin B12 is also very important as it maximises the absorption of folic acid. Taking a multi-vitamin tablet designed especially for conception is a good way to ensure you're getting enough of these valuable nutrients. Marmite is also a great source! (credit:Alamy)