The Sex Files

It looks like your kindergarten gut reaction to kissing might have been correct after all: it really is sick. Or, more specifically, the practice is designed to spread sickness. British scientists say the human habit of kissing evolved for less-than-romantic reasons, but one that is nonetheless important to a healthy reproductive relationship: to spread germs.

It only takes about 20 minutes after the last time you had sex to become a "virgin" again. That's if you've shelled out $29 for the Artificial Virginity Hymen.

The product has been getting some press, after conservative Egyptian politicians said they want the product banned. They're concerned that brides might use the product to fake their virginity, according to a report by the Associated Press.

A pair of MIT students claim that they have created an algorithm that outs gay members of Facebook by analyzing the sexual orientations of their networks of friends.

The students first analyzed the networks of people who publicized their sexual orientation on Facebook. Turns out that statistically speaking, gay men have more gay friends than straight guys do. So then, they used an algorithm to run the stats on men who kept mum about their sexual orientation on the site. Their computer program was able to correctly identify 10 men whom the students personally knew to be gay in the real world but who hadn't shared that fact on Facebook.

According to a new report from the prestigious London School of Economics, birth control is a less expensive way to reduce carbon dioxide emissions than most green energy strategies.

Sex for a female Lake Eyre dragon lizard is sometimes like going to bed with a man and a roaring chainsaw. The male lizard bites her neck before mounting her. If he sinks his teeth in with too much vigor, he can chomp her spinal cord and kill her.

So it's no wonder the lady lizards are choosy about sex.

When it comes to contraception, women have their pick of techniques. In addition to sperm-blocking barriers and foreign objects in the uterus (IUDs), there are about a million ways to pump extra hormones into the bloodstream (pill, patch, ring, shot, or implant).

For men, it's always been pretty much condoms or a vasectomy.

Our sperm and eggs give us one of the greatest responsibilities on the planet: the potential to generate new life, to put forth onto the Earth another living, breathing, thinking, feeling being. Or, they can be sold for a buck.

Making babies requires a male and a female, a sperm and an egg, right? Well, the wild world of animals is often more creative than the lot of us humans when it comes to making whoopee. In fact, some animals don't have sex at all, thank you very much.

Just this month, bug biologists found the first all-female ant species, Mycocepurus smithii. The queen ant clones herself by making eggs that develop into adult females without fertilization. Some of those females will then become queens themselves. Apparently the species has been sexless for enough generations that the ants might not be able to mate even if they wanted to. Dissections showed that a key female sex part that normally interlocks with a male organ during mating had shrunken to a ghost of its former self.

It has long been known that contracting HIV through oral sex is rare. Klara Hasselrot of Stockholm's Karolinska Institutet recently wrapped up a study--detailed in a forthcoming paper in the international AIDS journal AIDS--that might shed some light on why this is. It provides the first-ever evidence that humans can develop resistance to HIV in their saliva.

Good news, crackheads! You can now smoke, snort, or freebase with impunity while pregnant, and your baby will probably only turn out a little weirder than it would anyway.