Page "XY sex-determination system" Paragraph 13

In mammals, including humans, the SRY gene is responsible with triggering the development of non-differentiated gonads into testes, rather than ovaries.

However, there are cases in which testes can develop in the absence of an SRY gene ( see sex reversal ).

In these cases, the SOX9 gene, involved in the development of testes, can induce their development without the aid of SRY.

In the absence of SRY and SOX9, no testes can develop and the path is clear for the development of ovaries.

Even so, the absence of the SRY gene or the silencing of the SOX9 gene are not enough to trigger sexual differentiation of a fetus in the female direction.

A recent finding indicates that ovary development and maintenance is an active process, regulated by the expression of a " pro-female " gene, FOXL2.

In an interview for the TimesOnline edition, study co-author Robin Lovell-Badge explained the significance of the discovery: