She is the author of This is Not Your Mother's Menopause: One Woman's Natural Journey Through Change (2000), No Hormones, No Fear (2003)[1] and The Pharmacist of Auschwitz: The Untold Story (2017).

"[8][9] She has also written articles and profiles for national magazines, including Salon, The Huffington Post, and The Daily Beast.

[12][independent source needed] The book received praise from Michael Granberry, Arts Critic for The Dallas Morning News, and was on The Wall Street Journal Nonfiction Bestseller list at number 6 on 21 January 2018.

[15][independent source needed] In 2022 Posner appeared on Richard Helppie's Common Bridge podcast where she argued that the use of gender-neutral language in medical contexts "erases women" and expressed concern about transgender athletes and transgender people using bathrooms or dressing rooms corresponding to their gender identity.

[4][16][independent source needed] In 2007, she was at the center of a controversy, regarding whether a journalist could express an opinion opposed to that of her publisher on a public issue.

"[17][independent source needed] Her 2007 Wikinews interview sets forth the limits and risks for a journalist when it comes to disagreeing publicly with publishers.