Should I get my son the guardasil vaccine?

I would. The germ passes easily & quietly between carrier & recipient. Barrier methods don't always prevent the spread. It may never show any signs at all in a male before he passes it on or gives it to his future spouse. Random blood tests in the pre-vaccine era showed ~ 70% of college females were positive for signs of prior infection by their junior year.
Agree and... I agree with the author above. In addition, though many men never show signs of hpv: 1% of sexually active men in U.S. Have genital warts at any one time each year 2, 000 men get hpv cancer of the penis & anus. Each year 5, 600 men get oral cancer from mixed hpv & smoking. Men with HIV who get hpv have a high incidence of genital warts. Why risk any of this? Once positive for hpv, vaccine too late.