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February 14-21 is National Condom Week in the United States.

There are few things more annoying than a pair of shoes that rub the wrong way. Too loose, too tight: you just want to get them off.

It turns out it’s the same with condoms.

According to the February 2010 issue of Sexually Transmitted Infections, men saddled with an ill-fitting condom are twice as likely to yank it off in the middle of having sex as men who have the right fit. The Kinsey Institute and University of Kentucky researchers found that a full 44.7% of men report using condoms that didn’t fit quite right.

That’s bad news for anyone trying to lower their exposure to STIs—or a huge surprise nine months down the road. Remember the movie Knocked Up?

Part of the problem may stem from pride. There are likely fewer men ready to reach for SM or MED when L and XL are right there. And the problems that come from making the wrong choice are myriad, according to the 436 men surveyed in the study: torn or slipped condoms, reduced pleasure, difficulty climaxing (for men and women), irritation, etc., all the way to let’s just take the damned thing off.

It may come as little surprise that men’s minds are not at their clearest while in the grip of passion. It is, however, a bit of a shock that someone has actually quantified the phenomenon. In a study entitled, “Bikinis Instigate Impatience in Intertemporal Choice,” published in the September, 2007 Journal of Consumer Research, researchers set out to determine if men "exposed to sexual cues" will make choices based on immediate gratification, rather than longer-term reward. Turns out they will.

The odds are already only 1 in 2.53 that a male 15 - 44 used a condom during his last sexual encounter, which means that, even before taking into account heat-of-the-moment removal due to ill fit, only about 39% of men 44 and under use condoms. However, when we break down the numbers, a lower ratio of married men in this age group use condoms (1 in 4.17), as might be expected, but a higher ratio of never-married, non-cohabiting males make sure they are protected (1 in 1.54, or 65%). So those who advise “if you love her, wear a cover” might want to add, “preferably one that fits.”