In her teshuva, she provides several approaches to emulate the complicated counting cycle that tallies the days a woman is considered ritually impure following menstruation. She suggests using a seven- and 11-day cycle originally proposed by Maimonides, the 12th-century scholar and philosopher. De Cordova also suggests that the imposition of a cycle not based in biology means ancient and medieval rabbis had some understanding of womanhood as a social construct.

https://www.timesofisrael.com/queer-yeshiva-publishes-first-set-of-jewish-legal-opinions-by-and-for-trans-jews/