During ejaculation woman's vagina gets about 300-500 million sperm. Among the vagina most of them die, only the most persistent fall in the cervical mucus. There locomotor activity of sperm increases, However, before we get to the egg, they must cross the uterine cavity and into the fallopian tube. On all this way sperm spend about 2 hours. Fertilizing capacity of sperm stored for 2 days. The ovum is the bearer of sexual X-chromosome, and sperm are of two types: carriers of X-and Y-chromosomes. When the egg fused sperm carrying the X chromosome, the embryo is female (XX), and if sperm with a Y-chromosome, the embryo male (XY). There is one more or less "scientific" method of planning sex of the child, which is based on differences in the properties of sperm.
Sperm carrying the male Y-chromosome, more mobile and able to reach the egg before. However, sperm with the female X chromosome is more viable – it can survive longer in the fallopian tube, 'waiting for' the moment of ovulation. This method is called by Otfried Hattsolda. Believe that this method of planning baby's sex is effective in 80% of cases. In practice, it looks like this: to give birth to a boy – to abstain for 1 week before the day of ovulation, sexual intercourse, in this case better to have the day preceding or coinciding with the day of ovulation to give birth to a girl – the last sexual act must be no later than 2-3 days before ovulation. How to identify the forthcoming ovulation? For an accurate determination of the day ovulation in the modern world, women use compact tests, microscopes, working on the effect of "fern" in the crystallization of saliva. Typically, a healthy woman is ovulating at 12-16 day menstrual cycle. On the day of ovulation, most women experience a slight abdominal pain and mild nausea.