FemHealth Ventures is the first fund to formally define women's health investing through its proprietary three-category framework of "only in women, mostly in women, and differently in women," which has been widely adopted across the sector since 2019. The fund builds its investment thesis on the biological principle that every cell has a sex, emphasizing that all cells in a woman's body have XX chromosomes versus XY in men, requiring sex-specific treatment approaches across drugs, devices, diagnostics, and digital technologies.