"Approximately a decade ago, Meng et al. and Cui et al. discovered a novel source of MSCs from human menstrual fluid, named menstrual blood-derived stem cells (MenSCs). Throughout these years, more and more studies are focusing on MenSCs, a representative comparison was presented in six sources of MSCs, suggesting that MenSCs possessed higher proliferation rates and painless procedures, and almost no ethical issues."
January 1, 1970
https://en.wikiquote.org/wiki/Menstruation