It is all in the timing. It is possible to choose the sex of your baby before you conceive. When we conceive we have a 50 percent chance of having either a boy or a girl. This method of sex selection has been used for 100s of years. To understand how to select the sex of your baby you need to understand how nature selects the sex.
Male semen carries the sperm cells that determine the sex of the fetus.
The woman carries ovums or eggs in her ovaries, each of these eggs has only the X chromosome. Females usually only release one egg each month and it is available for fertilization for only about 2 days. Males release millions of sperm each time they ejaculate and only one of them will get to fertilize the egg. Most of those million sperm die on their trek through the cervix and up the fallopian tubes looking for an egg. Only about a thousand sperm cells will actually make it to the egg.