There was a study recently that links pubic hair grooming and STI's:
"Correlation between pubic hair grooming and STIs: results from a nationally representative probability sample"
E Charles Osterberg, Thomas W Gaither, Mohannad A Awad, Matthew D Truesdale, Isabel Allen, Siobhan Sutcliffe, Benjamin N Breyer
They say that grooming can cause "microtears" in the skin creating access points for viruses. They cite a case where HIV was transmitted between brothers using the same blade, although they also state that this kind of transmission is extraordinarily rare. I thought that HIV is rendered inactive outside the host, therefore unable to infect. If this is true, then what about barber shops, they use the same blade on people all the time. Should we be rethinking this possible route of transmission?