The renal segment supplying an ectopic ureter is nearly always dysplastic. Usually the ureters cross and the ectopic ureter terminates caudally in relation to the ureter from the normal portion of the kidney. Extravesical termination in women leads to urinary incontinence, since it frequently ends in the vagina or the labia. In men, the effects are much less noticeable. The ureters usually terminate in the urethra, the seminal vesicles, the ductus deferens or the epididymis. Duplication of a ureter or mega-ureter with dysplasia of the appropriate part of the kidney can be readily explained embryologically.