Well this is a kind of great secret that I would like to share with everybody. Modern science relies on X and Y-chromosomes
for birth of male and female child, but Indian ayurveda follows different theory on this.
According to Ayurveda birth of male and female child depends upon having sex after particular number of days after mensuration. This experiment is done on number of couples and eight out of ten couples have given exact results.Explaination with the help of example will clarify things better.
For an example if mensuration started on 10 of June. Count this as the first day. And say it lasts for four days. Having sex in these four days will no lead to pregnancy, but having intercourse on even night in the fertile period after this day will produce male child. Means sex done on 16,18 20 etc will lead to male child. And having sex on 15,17,21 will lead to female child. This is a phenomenal theory and not many people know about it. Its just gone in to dump as rest of ayurveda.