Ovulation occurs in the woman each month due to a number of hormonal
and anatomical changes. 
Several parts of your body are involved in the process of ovulation.
(How to calculate ovulation? contact for detail).

you’ve probably spent a lot of time in your life trying not to get pregnant.

But now, if you're trying to have a baby BOY or Girl,

it can be astonishing to realize you have only a small window of time
each month when you can conceive, typically about three to four days.

Those days are determined by when you ovulate and indicate in the calendar

when your ovaries release a ripe egg that will await fertilization
or, as happens most months, when that egg, unfertilized, triggers menstruation.