Dear Cecil: My boyfriend and I need some answers. You're the only one we can turn to. Please don't think we're weird. (1) Does taking a hot bath (120 degrees) kill sperm? He says he'll be sterile for a month. (2) Can blowing air into the vagina during oral sex really cause an air embolism and sudden death, as per Joy of Sex? Francine M., Chicago

Cecil replies:

I don’t think you’re weird, sweetie, but you might want to keep an eye on that boyfriend of yours. The mobility of sperm is reduced at temperatures above 104 degrees or so, and “spermatogenesis” — the creation of new sperm — is slowed. But the effect is brief — maybe half an hour, a researcher at the Masters and Johnson Institute guesses — and it certainly doesn’t affect all the sperm. Remember, it only takes one to get you pregnant. Hot baths are not recommended as a method of contraception, and they certainly won’t make a male sterile for a month.

The bathtub can be an effective birth-control device when used properly, however. It can be used for cold showers, for example, and it has been proven beyond reasonable doubt that conception can be prevented when one of the partners lies completely motionless in the tub while the other stays in the bedroom.

This business about blowing air into the vagina is a lot more serious. It definitely can cause embolism and death, particularly if the woman is pregnant. Ten fatalities and one near-miss had been reported in the medical literature as of 1983. During pregnancy the vagina is distended, allowing substantial quantities of air to be introduced. The air enters the bloodstream via the vein sinuses of the intrauterine wall and from there finds its way to the heart and the brain. Collapse is usually immediate, and death can occur within minutes. In the one non-fatal case, proper treatment was delayed in part because the victim’s male partner didn’t tell doctors what had happened until two hours after she was admitted to the hospital. The woman miscarried and, despite treatment in a hyperbaric (high pressure) chamber, suffered permanent brain damage. How likely such things are if the woman is not pregnant is not clear, but if I were you I wouldn’t try it under any circumstances.

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.