The term infertility is used when referring to the biological or physiological inability to conceive a baby when unprotected sex has been practised for a period of twelve months or more.
It is also commonly used to describe the unsuccessful attempts of a woman carrying a pregnancy the full nine months and a when miscarriage occurs as a result.
There are so many causes for infertility but recent study results have shown that women as responsible for around two thirds of cases, the rest are related to irregular sperm problems and other factors of an unknown nature.
In women, infertility is more often than not related to deficiencies and imbalances of hormone levels, problems with the reproductive organs and occasionally with illness, although chemical disturbances from surgery, mechanical trauma and potent medications are just some of the additional factors which negatively affect the rate at which a woman conceives.
Globally the most common cause of infertility in women is probably Pelvic Inflammatory Disease, or PID as it is frequently referred to.
The structure of the reproductive organs and the pelvic area in general is attacked by this infection and conception is made increasingly difficult.
The long drawn out exposure to microorganisms and the scarring as a result of the infection has been known to cause blood poisoning and on the rare occasion that conception is successful, there is a high chance that the pregnancy will be ectopic.
Adrenal gland and thyroid deficiencies often bring about hormonal and ovarian problems as when these two organs fail to operate as they should an increase in prolactin happens.
This is the hormone that stimulates breast milk production but it also stops ovulation taking place as well.
High levels of prolactin may suggest the presence of a pituitary tumour as well as making conception extremely unlikely.
As a result of many kinds of vaginal or abdominal surgery, infertility may be caused by the scarred tissues.
The traumatized areas make it very hard for the egg cells to be transported from the ovaries to the uterus along the fallopian tubes.
This is also the reason why conception often takes a long time after previous abortions have been carried out.
The remaining scar tissue stands in the way of the sperm fertilizing the egg.
Taking antibiotics, anti-inflammatory medicines and anti-depressants can also be responsible for reducing the chances of conception.
This happens because the amount of estrogen and luteinizing hormones is decreased and higher levels of these are needed to bring the egg to maturity ready for release.
So that's what it's all about as far as the females of the species are concerned so now we can move on to the male side of things.
It's usually sperm related problems that are responsible for infertility and the characteristics, the quality and the sperm count (or complete lack of sperm in some instances) are important factors here.
When the sperm cells are not of good quality they tend to move slowly and often due to their abnormalities they don't manage to reach the egg and fertilize it.
The reason for poor quality in sperm cells could be down to many factors, one of which is the failure of the testes to drop and continue to develop in the right way - they sometimes don't drop and develop at all and simply remain in the main cavity of the body.
In males the potent sperm cells release is often impaired by certain medication as well as exposure to particular metals.
When this happens the chemicals present can alter the molecular and physical make-up of the sperm cells and the ensuing lack of movement of the cells means that conception is not likely to take place.
The question of what causes infertility has many possible answers and the fault can be with females and males alike.
However, if you or your partner has been diagnosed as infertile, there is no need to give up hope altogether - not nowadays when there are so many natural and conservative treatment options open to you as a way of remedying the situation.