Erectile Function and Sexual Activity Are Declining in the Younger Generation: Results from a National Survey in Japan. - Tsujimura A; Fukuhara S; Chiba K; Yoshizawa T; Tomoe H; Shirai M; Kimura K; Kikuchi E; Maeda E; Sato Y; Nagai A; Nagao K; et al. (The world journal of men's health, 2025)