Such contact can also lead to more mundane infections from common bacteria and viruses found in, around and secreted from the genital regions.
Because of the aforementioned factors, medical sources advise the use of condoms or other effective barrier methods when performing or receiving oral sex with a partner whose STI status is unknown.
Additionally, gay males may regard oral sex as a way of maintaining their virginities, with penile-anal penetration defined as resulting in virginity loss, while other gay males may define oral sex as their main form of sexual activity.
However, the transmission risk for oral sex, especially HIV transmission, is significantly lower than for vaginal or anal sex.
Oral sex may be practiced by people of any sexual orientation.
Oral stimulation of other parts of the body (as in kissing and licking) is usually not considered oral sex.
Oral sex may be performed as foreplay to incite sexual arousal before other sexual activities (such as vaginal or anal intercourse), Like most forms of sexual activity, oral sex can pose a risk for contracting sexually transmitted infections (STIs/STDs).
Fellatio may reduce the risk of miscarriages by inducing immunological tolerance in the woman by exposure to the proteins in her partner's semen, a process known as paternal tolerance.