Well the truth is that it's mostly all chance. The sperm have a long and arduous journey to reach the egg, and influencing the outcome of the "great sperm race" to make sure a male sperm instead of a female sperm makes it there at the perfect time is somewhat laughable. Here are a handful of the most popular and circulated old wives' tales that are mostly hooey:

1. DO IT DOGGY STYLE
Because this position potentially puts the penis *slightly* closer to the cervix, thus helping the boy sperm get there faster.

Problem with this theory? (A) First of all, if the penis is closer to the cervix, or the sperm are given a given a smoother ride, that means the female sperm will be all the faster also. (B) Plus, being the first sperm on the scene does not mean it's the winner. If some sperm arrive too early, they won't be able to fertilize the egg. So the timing all boils down to luck/fate/chance on which sperm arrives at the precise right moment.

2. THE MAN SHOULD ORGASM FIRST
...because it'll encourage the more manly sperm??

Problem with this theory? It's actually contrary to the best medical advice, considering that female orgasm lubricates the path for the sperm and if anything may only help male sperm reach their target first. Perhaps this theory is more of an old husbands' tale...

So is there anything legitimate you can do? Outside of selective genetic medical procedures (which are new and controversial), here are the most legitimate theories that may help:

Time Intercourse as Close as Possible to Ovulation
++++++++++++++++++++++++++++++++++++++++++++
Because male sperm are fast, but not so robust, they shouldn't be swimming around any longer than absolutely necessary in a woman's system. Give them a straight path right to a waiting egg, and a finish line. If you have sex too early (a day or two before ovulation), then the males may arrive to early for the egg or be obliterated by the female body's natural defenses.

Have Your Man Drink Some Caffeine in the Hours Leading Up to Sex
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Caffeine tends to make the male sperm more active, and may help increase the chances for sperm to defeat obstacles and reach a waiting egg first (if your timing is right).

Remember though that all of these *maybes* and *possiblies* are all just ways to theoretically boost your odds. Without the direct assistance of medical professionals, there is no way to control the gender of your baby.

How can we increase the chances that it will be a boy?

1. Boy sperm are faster (because of the lighter Y chromosome) than the girl sperm, but they also die faster. So try to drop/spell your (male) semen as deep as possible in the cervix.

2. Having sex in the 1st day of dropping an egg (have sex the exact day of ovulate) by the female would increase your chances of having a boy.

3. Focus on the pleasure of each other; if the male climaxes first, you'll get your boy.

These are three basic, try to understand it and follow all your procedures.

Someone may say that try having sex from behind. The logic being that the sperm have an easier time getting up the tubes from that position, and since boy sperm are fast, they will make it before the girl sperm. That might be a myth, but it is worth a try. There is also this theory that the PH levels in vagina affect which gender you conceive.

COSTLY PROCEDURE:
PGD - PGD stands for Preimplantation Genetic Diagnosis. This process involves in-vitro fertilization in which the embryos are created outside the body and then tested for gender and genetic disorders. The biggest downside is that PGD can cost nearly $20,000 for a single round. Also, as with any IVF procedure, you are more likely to have multiples.

Source(s):
http://how-to-conceive-a-boy.blogspot.co…
http://www.associatedcontent.com/article…
http://www.newscientist.com/article/dn13…
http://www.amazingpregnancy.com/pregnancy-articles/288.html