After meeting with girlfriends who have read books, consulted doctors and - most importantly - compared success notes, we've assembled a list of the most common tactics they swear by:

The most important concept is timing your monthly cycle because it is key in helping to plan the sex of your baby. When you have sex during your cycle will depend on whether you want a boy or a girl. It's a little complicated, here's the theory behind the timing:

Sperm is made up of X-chromosome (girl) and Y-chromosome (boy) sperm. When X-chromosome sperm fertilize an egg, it results in a girl baby, Y-chromosome sperm result in a boy baby. The "boy" sperms are fast and tend to get to the egg faster, however they also die much more quickly than "girl" sperm.

The closer you have sex to your ovulation date, the better your chances of having a boy. If you have sex 2 ½ to 3 or more days before ovulation, the majority of "boy" sperm will have died by the time you ovulate, leaving a higher percentage "girl" sperm available when the egg is released and increasing your chance of having a girl.

The pH of a woman's vagina is also an important factor in planning for a boy or a girl. A more acidic environment, which naturally occurs near the front of the vagina, favors a more conducive environment to "girl" sperm so parents wishing to have a girl should use shallow or missionary-positions. The cervix area of the vagina is more alkaline - more favorable to the "boy" sperm. If you're trying for a boy, you should use positions that will deposit spearm in this deeper area.

If you want a girl:
Have sex every day from day 1 to day 5, then stop three days before ovulation.
The man should take a hot shower immediately before intercourse.
Women releases a substance at orgasm that will make the environment more alkaline, creating a more favorable environment for the "boy" sperm. If you are trying for a girl, the experts recommend no orgasms!

If you want a boy:
Don't have sex for 3 - 4 days before you reach your target date (a day or two before ovulation).
Your man should also drink a cup of caffeinated coffee right before sex.
If you have an orgasm, it will make the environment more alkaline, which favors boys.

For more scientific details about choosing the sex of your baby, the book "How To Choose The Sex Of Your Baby" by Dr. Shettles discusses charting cervical mucus, basal body temperature and using ovulation predictor kits.