AbstractCross‐sex hormone treatment of transgender persons is usually uneventful, but hormone‐sensitive malignancies of the (reproductive) organs of the natal and new sex (breasts, neovagina) may arise. Sex reassignment surgery impacts on the urodynamics of the reassigned sex. Pathology originating from organ systems of the natal sex may be overlooked in the new sex. In male‐to‐female transgender individuals, malignant tumors of the breasts and prostate may occur. Neovaginas are constructed with skin or sigmoid. Shortening of the male urethra to female dimensions is usually uneventful. In female‐to‐male transgender individuals breast cancer may develop, sometimes in residual mammary tissue after reductive mammoplasty. Malignancies of the vagina and ovaries are rare. Testosterone may be aromatized to estrogens, with effects on the endometrium. Lengthening of the female urethra to male dimensions may cause urethral fistulae, urethral strictures, and meatal stenoses. A degree of post‐voiding incontinence may occur.