Is that true? I thought it was only through the vagina that STDs are passed?
Using condoms for vaginal intercourse significantly lowers transmission of STIs (sexually transmitted infections) like chlaymdia, gonorrhea, Hep B, HIV, HPV and syphilis and are a tool to prevent pregnancy.
Your friend is right. Anal sex without a condom poses a risk for these same infections as well as Hep C.
Correct and consistent condom use will significantly reduce the transmission of STIs for vaginal, anal and oral sex.