HPV Vaccines - Just for Girls?

Is it just me, or am I missing something. We now have a vaccine for HPV. It does not protect against all strains of HPV, but does offer some protection against some of the worst strains. But it is being offered for young girls. Now I understand that young girls (and women of all ages) are affected more seriously by this virus than boys are; however, HPV can cause problems for young men too, and women might be better off if fewer men were spreading the virus.

Why is the vaccine only being offered to young women and not young men?