Wondering if your sweetheart is going to buy you a box of condoms instead of a box of chocolates for Valentine's Day? Maybe your lover's celebrating two holidays at once: February is also National Condom Month.

Yes, public health advocates chose the most romantic time of year to promote the condom, that ubiquitous rubber device that safe-sex folks love and most of us love to hate (including Seinfeld's George Costanza, as you'll see in this clip). Which isn’t to say it's not useful: 19 million new sexually transmitted diseases (STDs) occur in the U.S. each year, half of them among people ages 15-to-24, according to the American Social Health Association (ASHA). Latex condoms, used correctly, can prevent HIV transmission 80 percent to 95 percent of the time, according to a 2008 review in Sexual Health. They also reduce the risk of STDs, including gonorrhea, Chlamydia and trichomoniasis, the Centers for Disease Control and Prevention (CDC) says, and are 85 percent to 98 percent effective in preventing pregnancy.

It turns out that the condom has a long and, perhaps not surprisingly, entertaining history. There's disagreement about just how many years it's been used; Ansell, which makes LifeStyle condoms, dates the condom to 1000 BC, when the company says images of ancient Egyptians portrayed men wearing linen sheaths. "It's up for discussion as to whether they wore it for protection or for ritual reasons," Ansell notes on its Web site. But there's little debate that linen is best saved for summer slacks; Europeans used linen condoms in the late 16th century to reduce transmission of syphilis, notes Adrian Mindel, author of the 2000 book Condoms, adding: "It didn't work!"

The condom started getting a little more sophisticated in the 1700s, says Mindel, director of the Sexually Transmitted Infections Research Centre at Westmead Hospital in Sydney, Australia. Back then, condoms were made of animal membranes, most often lamb skin, which is still sold (but not recommended to protect against STDs).

The modern condom more common today was developed in the 19th century, following Dunlop's discovery of the vulcanization of rubber (a process that makes the material stronger and more elastic). "Latex is an excellent material, and it's impervious to even very tiny organisms, such as viruses," says Fred Wyand, a spokesman for ASHA, which started the celebratory National Condom Day in 1991, when AIDS drew attention to safe sex. (The celebratory day was extended to a month this year.) "Animal membrane condoms are more porous and more susceptible to allowing viruses to pass through, making them a less effective choice for STD risk reduction."

These days, there are condoms featuring the face of recent presidents or candidates, including an Obama condom to "use with good judgment."

Given the ever-present high number of STDs, though, you might wonder if people actually use condoms. That's a tough behavior to reliably track, but consumers are buying them. Men's condom sales were up 4 percent to $312 million during the year period ending January 24, though in terms of quantity, sales were down 0.3 percent, to 437 million condoms, according to Nielsen Co. But condom sales were up 6 percent in the 4th quarter of last year over the same period in 2007, with 2 percent more condoms purchased over the fourth quarter in the previous year. Here in New York City, where our venerable Mayor Bloomberg encourages residents to "get some" NYC-branded condoms, officials have distributed a whopping 70 million of the city's free rubbers in the last two years.

On Wednesday, the NYC Condom joined Facebook. Though the condom has been discreet so far about its relationship status, we wonder if the NYC health department will tweet tomorrow, when it's invited New Yorkers to celebrate condoms in "a room of your choosing."