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

Sex determination happens on different levels.

Chromosome is the fundamental one.

Because Y chromosome has the message (genes) to produce (Testosterone), which is lacking in X chromosome, fetus with XY pair can modify the gonad (which is same for both male and female until 6-7 weeks of life) to a male.

Generally speaking, it is this influence of Testosterone that makes us male. If we can block the effects of testosterone, even a fetus with XY can be a female with Ovaries and vagina as our default development is to be a female.

But, even when there is chromosome, the downstream signal translation requires a lot of different receptors.