At 18 months or so, a girl's vocabulary consists of about 90 words, compared with 40 words for most toddler boys. So to boost the odds of having a girl, mothers should say, yes, to calcium and magnesium think yogurt, spinach, tofu, almonds, cashews, beans, oatmeal, broccoli and oranges and, no, to salt and potassium anchovies, olives, bacon, salami, smoked salmon, shrimp, potatoes, processed meats, bread and pastries. Controlling Fertility Without Drugs or Devices reports that couples who tried to conceive a boy were successful, while only four were not. Combine a strict diet with some carefully orchestrated sex — to increase the likelihood of having a girl, the researchers recommend avoiding sex immediately before and after ovulation — and apparently it can make all the difference. Girls usually use cloth, towels or tampons to absorb the blood and protect clothing. What do you think? Periods generally last between 3 and 5 days. There is a theory that male sperm swim faster and die off first so to have a girl you would aim for a few days before ovulation so those slower stronger girl swimmers are the ones to fertilise the egg. Print Shutterstock Whether you're ready to know your unborn baby's sex now! Ejaculations are the way your body pushes out semen sperm and other fluids through your penis. Breasts Your nipples and breasts will start to fill out during puberty.