Some couples who are trying to conceive have specific preference regarding the sex of their baby. Perhaps they have two girls already and are hoping for a little brother for them. If you are trying to conceive a boy and are searching for tips how to improve your chances of having a boy, the following are the things that you could do to improve your odds.

The method is based on the fact that the male sperm (with Y chromosomes) and female sperm (with X chromosomes) have some distinct characteristics.

Male sperm are smaller and lighter, but quicker than female, so they can reach the egg faster than female sperm. Male sperm also has a very short lifespan, unlike the female sperm which can live for days. It also prefers a more alkaline environment. Female sperm are bigger and stronger, so they can survive for longer periods of time, but they are also slower.

• To conceive a boy, you should try to have sex close to the time of ovulation – the window of for conceiving a boy is 24 hours prior to ovulation to no more than 12 hours past ovulation. You should closely monitor your cycle using one or more methods of ovulation prediction. These methods are charting cervical mucus, charting basal body temperature (BBT), and/or using ovulation predictor kits (OPK).
  
  If you have not been charting your cervical mucous or basal body temperature, then using an OPK may be the easiest for you. An ovulation prediction kit when used properly allows to precisely identify the exact time you ovulate.
  
  Ovulation kits work by detecting when your luteinizing hormone (LH) levels increase. The LH levels surge about 12-48 hours prior o ovulation, so the optimal time for an intercourse would be about 12 hours after the LH surge (see the illustration below). As you get close to ovulation, you should do the OPK test two times a day to catch the surge as soon as it happens.
• You should also try to have sex in positions that allow for maximum penetration. This will increase the chances of survival of male sperm on the way through the vaginal opening, where the environment is more alkaline and less friendly to the male sperm.
• Another factor is a woman's orgasm, which can affect the vaginal PH as well. If the woman has an orgasm, it creates an alkaline environment in the vagina that is more favorable to boys.
• Additionally, eating foods which are naturally alkaline is said encourage more alkaline environment within the vagina.
• To minimize your chances of conceiving a girl, DO NOT have sex in the few days just prior to ovulation (or if you do, use some sort of birth control), that is as soon as your fertile cervical mucous appears. Female sperm are slower but also stronger and more resilient, so it is more likely you will conceive a girl if you have an intercourse during that time. The girl sperm will wait in the woman’s reproductive tract ready to fertilize the egg when it is released from the ovary. Most of the male sperm will not survive such a long wait.

These suggestions are based on the theories of Dr. Shettles. Some sources claim that the Shettles method, when properly applied, may give couples 75 % chance for success in chosing the sex of their child. Of course, there is no guarantee that you will conceive a boy, or even that you will become pregnant in the first place.

IMPORTANT: Remember that with this method you are reducing the number of days you have intercourse, which reduces your odds of getting pregnant.

On average, the chances of getting pregnant each month are rather low. Even healthy couples without any known fertility issues who are trying to conceive should remember that success may take time and effort. There is an approximately 25 % chance that the sperm will fertilize the egg; so a healthy couple who times intercourse properly has only a 25 % chance to conceive each month. The fewer days that you have intercourse while you are fertile, the lower your odds of getting pregnant.

If you are really determined you may try a more technologically advanced - but also more costly - method of gender determination. Have your partner's sperm spun and then have intrauterine insemination procedure with only male sperm. This method is close to 100% effective. Boy sperm are lighter than girl sperm. When the sperm is spun in a container it causes all of the boy sperm to float to the top while all of the girl sperm sink to the bottom. This method will cost about $500.00.