As I understand the medication, Viagra does not induce erections if the man is not psychologically excited. In other words if a guy is turned-off a Viagra tablet can't turn his penis "on." What is will do is increase blood flow to the organ for firmer, longer lasting erections when a guy is stimulated.
For older men (55+) this has got to be great: I've heard Cialis works even better than Viagra with the older generation. But if you've checked the prices on any of the top erectile medications (Viagra-Levitra-Cialis) the pharmaceutical companies are charging these guys exorbitant amounts (30 10mg Cialis/ $380.00) of money for a hard-on. Obviously older wealthy impotent Baby Boomers are the target demographic.
Gisella, I beleive the generation of men who need this medication are old enough to be your father and be assured that the erection you see is caused because of you, not some little blue tablet.