People always concern about the factors which can affect the sexes of their babies. More and more young couples want to have girls, as girls are relatively considerate and thoughtful. Although there is no scientific statement about the factors which can decide the sexes of the babies, people still want to control the sexes of their babies by themselves. Generally speaking, the factors which are always mentioned among people include the age, profession, pressure, diet and even men’s dress. 

When men grow older and older, the amount of sperms will be gradually reduced. Therefore, the rate of having girls will be increased. Under the action of aging, the secretion amount of alkaline substances can also be reduced when women grow older and older, which can increase the probability of having girls. Therefore, the rate of having girls of older couples is higher than that of younger ones.

According to the research, if a man works as a driver, an aviator or a diver, the probability of having girls can be increased. If the male didymus goes through the strong changes of high temperatures, atmospheric pressures and hydraulic pressures, the y-sperms which are not strong enough will die prematurely. Therefore, the chances of having girls can be increased.

The pressure factor also plays an important role in affecting the sexes of the babies. The long-term pressure can reduce the amount of the male sperms. In addition, a kind of acid environment can be produced by high pressure inside the female body, which is unbeneficial to the survival of y-sperms. Therefore, the couples who are always bearing high pressure of work and life can probably have girls.

According to the medical research, the diet factor can indeed affect the sexes of the babies. If the couple wants a boy, the wife should frequently eat some alkaline foods and the husband should adhere to a kind of balanced diet. If the couple wants a girl, the wife should avoid eating too many alkaline foods and acid foods so as to keep herself healthy, and the husband should also adhere to a kind of balanced diet. Alkaline foods include beans, vegetables, fresh milk, tea, kelp, calcium, vitamin D and so on. Acid foods include meat, fish, chocolate, drinks, corn, and vinegar.

All the factors mentioned above are just inferred or guessed by people. People should not depend on them to change the probability of having boys or girls blindly.