Medicines taken to treat cancers and endocrine disorders some cause infertility. Medicines taken as part of a surgery may also affect the fertility of a person.

Anabolic Steroids have been used by athletes to improve strength and performance for many years Among other side effects, anabolic steroids induce hypogonadotropic hypogonadism with associated azoospermia or oligospermia, abnormal sperm morphology, motility and testicular atrophy. These effects result from negative feedback of androgen on hypothalamo-pituitary axis and possible local suppressive effect of excess androgens on the testis.

The management of cases with infertility secondary to anabolic steroid abuse is controversial and range from watchful waiting with spontaneous recovery of spermatogenesis to hormonal intervention. The spontaneous recovery of spermatogenesis has been documented with high variability. Eventual successful return of fertility may be suspected by slow recovery of gonadotropins (FSH and LH). The hormonal treatment of hypogonadal hypogonadism with intramuscular injection of HCG and HMG and subsequent maintenance HCG injection has been proposed, if no improvement occurs longer than 6-24 months after discontinuation of steroids.

Use of antibiotics. Little is known of the effect of antibiotics on human fertility.  The common manifestations are spermatogenic arrest and impaired sperm motility and morphology. Examples of evaluated drugs are nitrofurantoin, erythromycin, gentamycin, neomycin, tetracyclin, sulfasalazine, penicillin G,  ampicillin.

Limited human studies addresses the effect of Recreational drugs on fertility. Sperm concentration and motility were found to be low in cocaine and marijuana addicts.

Consistent use of contraceptives are known to bring down natural fecundity.