Your statement is incorrect. Sex is determined at conception by the child either getting an X or Y chromosome from the father.
What happens later and has often been misunderstood is that there is a hormone release around the seventh week and after that the child begins to show either male or female characteristics.
The hormones do not cause a child to be male or female, they happen because the child is either male or female.
Oversimplification: Up to a certain point in gestation, a male fetus cannot be distinguished from a female one, except chromosomally. After all, a male fetus has both X and Y chromosomes, while a female has two X chromosomes.
All fetuses begin their development as females. This is when the X chromosome that both sexes carry influences the development of the fetus. After some point, the effects of the Y chromosome (hormones, etc.) transform the fetus into a male, while in the absence of the Y chromosome, the fetus continues to develop as a female.
In that sense, all males are genetically mutated females.