For the "average" women menstrual cycle takes about 28 days to complete beginning on the first day of your period.
This cycle begins with a fluctuation in hormone's which trigger the growth of an ova. Once the ova matures, it begins to make it's way down the fallopian tubes and into the uterus where it will patiently wait for it's companion. Should the ova become fertilized, it will embed itself into the wall of the uterus and begin to multiply and grow. If not, the uterus flushes it out and begins again.
So how can you tell when you have ovulated? There are two common methods that don't require a Doctor's appointment.
The first is a fluctuation in body temperature. This rise is minute and requires the careful observation of your temperature each morning until you can recognise the increase.
The second is preferred by most mothers-to-be. It involves a test kit not unlike a pregnancy test. The ovulation test works by measuring the amount of hormones in your urine sample.
However you don't need these ovulation tests to work out when it's the best time to try and get pregnant after your period. If your menstrual cycle takes 28 days then you are most likely to ovulate after two weeks from the first day of your last period. If your cycle is a few days longer then you will ovulate a few days later. If your cycle is a few days shorter, than you will ovulate a few days earlier.
So that's your cycle but we're forgetting something...
That's right...the men. Sperm is only viable for a few days after it's "donation" so it's important to time yourself perfectly.
This is where it gets tricky and you're probably wondering "Gee, it's a wonder anybody can accidentally fall pregnant!"
The ova carries the female chromosome by default - this means that the gender of your baby is determined by which sperm manages to enter the ova first.
Have you ever wondered why men have that competitive nature? It goes all the way back to the day of their conception. Confused? Let me explain.
The Y-chromosomes (males) are faster swimmers - aah, so that's why they always finish first!! =)
The little girl swimmers (or X-chromosomes) take on the slow and steady approach, they aren't as streamlined nor as strong as the X-chromosomes BUT they have the advantage of being more durable (that's right...they have a better pain tolerance!) They are more likely to survive longer in the acidy conditions on the way to the uterus.
Therefore in theory, if one were to have sex in the days prior to ovulation, many of the boy sperm will have died off. Where as if you were to have sex after ovulating, the little boy sperm are more likely to race ahead and get there first.
Please realize however, that this is simply a gambling of odds, there is no way to determine, let alone choose, the gender of your baby...but by all means, you can have fun trying!