A man with gynecomastia and infertility, cause?
Cimetidine (but not other H2 blockers) has antiandrogenic action. It displaces dihydrotestosterone from its cytoplasmic receptor. 
It also increases plasma prolactin and inhibits degradation of estradiol by the liver. 
High doses given for long periods have produced gynaecomastia, loss of libido, impotence and temporary decrease in sperm count leading to infertility.
Digitalis
Omeprazole
Erythromycin
Cimetidine