Ovaries must suppress their inner male

"This shows that the maintenance of the ovarian phenotype is an active process throughout life," Treier said. "Like Yin and Yang, FOXL2 and SOX9 oppose each other's action to ensure together the establishment and maintenance of the different female and male supporting cell types respectively."

Further analysis showed that FOXL2 works in cooperation with the estrogen receptor to repress Sox9. Without FOXL2, the estrogen receptor fails to work suggesting that loss of estrogen levels could lead to sex reversal. Treier suspects that this mechanism might underlie the occasional signs of masculinization seen in menopausal women.

"When estrogen declines [in menopause], part of the ovary may switch to a testicle-like structure," he said."

Ovaries must suppress their inner male