In a developing fetus, what influences whether it is going to become male or female? What influences the cells to start building male or female organs?

Question

In a developing fetus, what influences whether it is going to become male or female? What influences the cells to start building male or female organs?

In: 274

Answer 1

That is the presence or absence of the Sex-determining region Y protein (SRY), which is typically found in the Y-chromosome. Hence the X and Y theory, that XX is female, XY is male, but that theory is outdated.

The SRY gene can be absent or inactive in the Y chromosome or be present in the X-chromosome. So you can be XX chromosome and still develop male reproduction organs or XY and develop female reproduction organs. Or you can be XXY.