Retrograde ejaculation is often due to Diabetes mellitus Neurologic dysfunction Retroperitoneal dissection (eg, for Hodgkin lymphoma) Transurethral resection of the prostate Sperm emission can also be impaired by Obstruction of the vas deferens or ejaculatory ducts Congenital absence of both vasa deferentia or epididymides, often in men with mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene Absence of both seminal vesicles Almost all men with symptomatic cystic fibrosis have congenital bilateral absence of the vas deferens, but the vasa deferentia may also be absent in men with mutations of CTFR that do not cause symptomatic cystic fibrosis.