The sex of a baby is determined by the type of sperm that fertilises the egg. If you want to know how to conceive a boy, you must first understand how gender selection works.

There are 2 types of sperm, X-sperm and Y-sperm. The X-sperm contain the X or female chromosome, and the Y-sperm contain the Y or male chromosome. So if you want to conceive a boy, a Y-sperm must reach and fertilise the egg first.

Most methods regarding how to conceive a boy are based around giving the Y-sperm an advantage over the X-sperm, increasing the odds the Y-sperm fertilises the egg.