Research shows a higher incidence of colorectal cancer in men . However, the molecular mechanisms for this gender disparity remain unknown . We report the roles of androgen in proliferation and differentiation of intestinal stem cells via targeting of the androgen receptor (AR) on intestinal stromal cells by negatively regulating BMP signaling . Orchidectomy (ORX) or the AR antagonist promotes expansion of intestinal epithelium but suppresses intestinal stem cell (ISC) proliferation . Conversely, the AR agonist inhibits ISC differentiation but augments proliferation in ovariectomized mice . Mechanistically, activation of the AR increases expression of BMP antagonists but lowers expression of BMP4 and Wnt antagonists in primary stromal cells, which promotes intestinal organoid growth . Interestingly, the BMP pathway inhibitor LDN-193189 reverses the ORX-induced effects . Our results highlight that stromal cells constitute the intestinal stem cell niche and provide a possible explanation for higher incidence rates of colorectal cancer in men.