We often take fertility for granted - particularly when we see so many headlines about underage pregnancies and unwanted children. This can be absolutely soul destroying for people who are desperate to have children of their own but find it difficult to conceive.

However many couples regard themselves as having a fertility problem way before they should. In western societies today, we tend to expect things to happen as and when we wish them to. Fertility is one of those areas however, where we have to listen to bodies and have to respect our own biology.

To conceive a human child, a female has to produce a viable egg which has to be fertilised within about 24 hours of release. Therefore, in each normal monthly cycle, there is only 124-hour period where a woman is fertile.

With the hectic lives that we lead, sometimes coordinating partners to be together at the correct time can be impossible, meaning that a viable egg may not become fertilised even though intercourse occurred just before or just after this 24-hour period. In addition, if a woman becomes stressed or anxious, she can alter her cycle and may not actually ovulate. Of course this worsens the problem, as failure to conceive often increases stress levels which and adversely affects ovulation.

Even if every egg is fertilised month after month, research suggests that only about one in five fertilised eggs is viable. The other four out of five have such bad genetic defects they would never grow into a living baby, and as such are ejected as part of what appears to be a "normal period".

Of course this means that in one year, if every one of the 12 monthly eggs are fertilised, only between two and three would be viable.

Not surprisingly, although couples tend to start getting anxious if they had not conceived within two to three months, just looking at the statistics no one should be surprised if it takes in the six months to a year to conceive naturally.

Before any fertility treatment is thought of, there should be a good six months of trying to conceive naturally and ensuring both partners are well rested, have good nutrition and are available at the relevant times.

If however it becomes clear that fertility is impaired, it is essential that medical advice is sought early. There are many simple things that can decrease fertility - males get low sperm counts if their testicles are kept too warm - such as wearing tight pants or having varicose veins around the testicle (a condition known as a varacocele). In addition smoking or high alcohol intake can have adverse effects and as such it is usually easier to examine and investigate the male first.

Of course with male egos, this is often a difficult time, and as such it is essential that both partners approach the problem together as a team and work with, and trust, their medical advisers.

Due to the anatomy, investigations of the female fertility is a little more difficult. However examination can show if there's any obvious hormonal abnormality and sometimes other medical conditions can be picked up by direct examination. Also a history of previous sexually transmitted diseases or partners that may have unwittingly passed such infections on, may have resulted in internal damage to the fallopian tubes even if no symptoms have occurred.

This now passes on into the realms of very specialist area and so specialist fertility experts and clinics have been set up to approach such examinations, investigations and then treatments with tact and care.

Although not everybody will end up having the baby they want, with modern day investigations and treatments, more people than ever before are having successful fertility treatment.