Estrogen was a female steroid hormone produced by the ovaries and by the adrenal cortex, placenta, and male testes.
In 2372, after transferring Keiko O'Brien's baby to Kira Nerys, Doctor Julian Bashir had to stimulate Kira's estrogen and progesterone production to enable the baby to metabolize Bajoran nutrients. (DS9: "Body Parts")
In a deleted scene from the Star Trek: The Next Generation fifth season episode "The Outcast", Beverly Crusher explains to Soren that women produce estrogen. [1]