The first answer is that it appears there is no way for the embryo to have its sex selected non-randomly. It's like throwing a coin, you end up with 50% chances

The first answer is that it appears there is no way for the embryo to have its sex selected non-randomly. It's like throwing a coin, you end up with 50% chances for each sex. The second answer is that there are indeed cases the environment can influence the chances for either male or female in several species. For example, mostly for reptiles, https://en.wikipedia.org/wiki/Temperature-dependent_sex_determination https://en.wikipedia.org/wiki/Temperature-dependent_sex_dete...