Male infertility: This can result from damage to the male reproductive tract and a variety of sperm disorders. One common cause is varicoceles, an enlarged vein in the sac beneath the penis. Surgery can sometimes help.
Enlarged prostate: Benign prostatic hyperplasia (BPH) affects around 1 in 3 men over the age of 50 years. An overgrowth of cells in the prostate gland causes the urethra to constrict, leading to problems with urination.