Conception is a lot more complicated than the act of joining the sperm with an egg. The timing and conditions must be right to ensure that it is successful. People naturally assume that conception will take place soon after they stop taking ‘the pill’ - it is a presumed natural and straightforward event.
Each time a man ejaculates, he produces sperm. However, for women it is usually only once that she will be ready to conceive in the month. Usually a fortnight before the first day of your period, you will produce a single egg from your ovaries. The egg swims to the fallopian tubes and lives there for approximately 12 hours. If it is not fertilised at this time, it dies and is absorbed back into the cells of the tube and the cycle starts again.
If you have sexual intercourse around the time you ovulate there is a big chance of conception taking place. Once ejaculation has occurred, the sperm (there could be up to 1000 million of them) separate from the seminal fluid and move up towards the cervix. The strong sperm survive this journey and the weaker ones die.
The vagina is quite an acid environment for the sperm and it takes resilient ones to withstand it. By the time the sperm reach the fallopian tubes, there are only two thousand left. The sperm struggle and fight to be the one to fertilise the egg when it is released. The one that connects with the egg is the fittest and strongest and this is natures way of ensuring that unhealthy or damaged sperm are not able to fertilise an egg.
Fertilisation occurs when a sperm penetrates the outer surface of the egg. Once the egg is fertilised, the tail drops off and the rest of the sperm die. The egg and sperm each with there own genetic information now combine together and form a single nucleus.
All this genetic information will determine the sex and characteristics of your child. The nucleus divides into two and over the next 3 days will continue to divide until there are 64 cells.
As this is happening, the egg travels through the fallopian tube towards the uterus. After the seventh day, the egg is able to snuggle into the lining of the uterus - now it can be nurtured and a pregnancy can start.
Once this happens conception is complete. The egg can be nourished by the blood supply in the uterine lining. At this time the ovary is informed that fertilisation has occurred and it stops ovulation and the body also ceases menstruation.
Occasionally however, the egg divides into separate halves, instead of doubling the cells in a single cell. The two separate embryos will be identical twins as they started off from the same egg and sperm. Non-identical twins will occur when two egg cells are released at ovulation and are fertilised by two different sperm.
Most couples find it reasonably easy to conceive, however sometimes it may take up to two years or so before it occurs. Other couples have great difficulties in conceiving and the problem can be with either partners or both.