August 20, The trees above illustrate how the gene works. As a result, they have an equal number of sons and daughters the great-grandchildren. The sex of the baby depends on which sperm gets to the egg first. Your Pregnancy Matters Is it a boy or a girl? However, embryos with abnormal chromosomes have a much harder time surviving until birth.
So why is the idea of natural gender selection gaining ground?
The father should also avoid excess heating around the genitals because heat destroys male sperm faster than female ones also, avoid tight-fitting underwear, saunas, hot tubs etc. This could be important for two reasons: the distance to the egg and the pH level where the sperm are first placed may give an advantage to one of the sperms types X or Y.
More Information Many ways that animals determine gender More about how the environment can affect sex ratios of children How the Y turns the fetus into a male.