But the prospect that they might wreck their sex lives just might make them stop and think. The same process by which smoking causes heart diseases is responsible for impotence. Atherosclerosis, or hardening of the arteries, can narrow the smaller blood vessels leading to the penis. In addition, nicotine makes blood vessels into and out of the penis narrow still further. While this effect stops immediately the man quits smoking, the arterial hardening takes some time to reverse.
Cigarettes sold in Thailand already carry impotence warnings.
The BBC is not responsible for the content of external internet sites.