Answer from:
Although gender selection is ethically wrong and medically not indicated, it is also illegal in the UK to select the gender for non medical reasons. Meaning it is basically linked genetically to genes being transferred through the sex chromosome, so we don’t. However there are some natural ways to favor a boy or a girl depending on the speed of the sperm. The faster sperm are the Y chromosome as it does not carry X and why? The Y chromosome is faster and lighter than the X. So as a kind of rule, you have a higher chance of boy if you have intercourse or insemination after ovulation and you have higher chances of a girl if you have intercourse or IUI before ovulation. This is a natural way of selection.
