If there's one thing that wakes me up in the morning, it's a sudden collision with another undefinable word. This morning it was a word I thought I'd understood for most of my life: virginity. As it turns out, it's suffered the fate of many a word these days:

It's all laid out in the new book Virginity Lost: An Intimate Portrait of First Sexual Experiences by sociology professor Laura Carpenter. She's now at Vanderbilt University in Nashville, but Carpenter was working at the University of Pennsylvania when she did most of her research in the last few years. She interviewed 61 Philadelphia-area residents about how and why they lost it.

Only two of them were still virgins, and none of the other 59 waited until marriage, she said, though one got close. There was, she found, some disagreement about what constituted virginity loss. Many argued that oral sex did not count as loss of virginity for straight people, but it did for gays and lesbians, which has a certain logic.

Then there are those borderline situations in which two people set out to have sexual intercourse but it doesn't quite work, she said. The parties involved may not even agree in such situations.

Needless to say, there's a double standard surrounding virginity for everyone, which, stubbornly, remains more of a stigma for women than for men:

Historically, virginity was always more of an issue for women, who were seen as property, and one who lost her virginity was considered "ruined" for potential marriage. In many cultures, it's believed that virginity can be "proven" if a girl retains her hymen, a small piece of skin that covers the vagina. Sometimes, but not always, the hymen will tear and bleed when a woman has sex for the first time. A small number of plastic surgeons around the country now perform "hymen reconstruction," apparently mostly for women from Muslim countries.

In America, we straddle a cultural chasm over premarital virginity loss, with some believing it's absolutely morally wrong and others seeing it more like pork chops - anathema to some people's religion, dangerous without proper preparation, but otherwise a fine thing.

There's little question about the historical importance placed on virginity, which is both a modern and an ancient virtue:

Virginity has been often considered to be a virtue denoting purity and physical self-restraint and is an important characteristic of some religious figures such as the Virgin Mary (often called simply the Virgin), the Ten Virgins and the Greek goddesses Athena, Artemis, and Hestia. The Maiden or Virgin is one of the three persons of the Triple Goddess in many Neopagan traditions. The constellation Virgo represents a wide selection of sacred virgins.

Female virginity is closely interwoven with personal or even family honor in many cultures. Traditionally in some cultures (especially those dominated by Christianity, Islam and Judaism) there has been a widespread belief that the loss of virginity before marriage is a matter of deep shame. In some countries, this loss has been linked to honor killings.

Some elements within western culture no longer regard premarital virginity as a virtue and may allude to it disparagingly. The increasingly-common belief of some western youth that virginity is no longer to be regarded as a virtue has become a matter of considerable debate, especially related to controversies involving sexuality among young people. Continuing virginity after a certain age is even regarded by some to be a negative thing, implying that the person is unattractive, prudish or sexually immature.

Some historians and anthropologists note that many societies that place a high value on virginity before marriage, such as the United States before the sexual revolution, actually have a large amount of premarital sexual activity that does not involve vaginal penetration, e.g., oral sex, anal sex and mutual masturbation. This has been termed technical virginity or hot virginity.

There's no longer any sure way to "trust but verify."

Still, it has always struck me that there's inevitably going to be an element of sexism involved. I attended an all male school, and most of my peers regarded the concept of "virginity" as a joke. Most of them lied, too -- and not about having kept their virginity. This "loss" -- something that's supposed to be a source of shame among girls -- was a source of pride among boys. When I was a kid, a boy was expected to lose his virginity, and he was expected to brag about having done so -- regardless of whether it was true.

Let's face it, folks, virginity has never been associated with virility. Why, I'd be willing to bet that more kids lie about having lost their virginity than about having kept it.

But let me return to penetration. In our attempt to be egalitarian and non-sexist about these things, I think that's what's being ignored.

At the risk of being sexist, I must ask: Is there or should there be any cultural distinction between penetrating and being penetrated? There's a stubborn but persistent belief -- among men and women -- that it's better to penetrate than be penetrated, and I don't see that going away.

Likewise, I see no practical way to avoid the ancient (if undeniably sexist in modern terms) feminine origin of the word virgin:

"Virgin" originated from the Greek and Latin word "Virgo," or maiden. It was used often in Greek mythology to classify several goddesses such as Artemis (also known as Diana) and Hestia. Virgin was a label of strength and independence -- it described the goddesses who were immune to the temptations of Dionysus, Greek god of seduction and wine. Artemis is the Greek virgin goddess of the moon and the hunt; she protects women in labor, small children and wild animals. Hestia is the Greek virgin goddess of the hearth. She never takes part in the struggle of men and gods. Virginity was once a term of power.

As we all know, the word virgin has "evolved" to the point where men and women have just as much right to be virgins. But is that really fair to either sex? What about common sense?

When a man loses his virginity, who's to know? There's no physical evidence, no bloodstained sheets, no pain. It's an event almost as ill-defined as "becoming a man." You're never quite sure it really happened, or when or sometimes even how. The whole business is so murky that, historically, virginity has been a term applied mainly to women. Because for a woman, losing it is generally a more clear-cut, tangible affair. The first time a penis penetrates her vagina is often memorialized with blood, pain or both. That's from the rupturing of her hymen, a fibrous membrane that may partly or completely cover the opening of her vagina.

Nor is it fair that women can have have their virginity surgically restored and men can't.

What's a man to do if he wants his virginity back? See the film about the 40 year old virgin and fantasize?

There's nothing fair about any of this.

* Might there be a lurking, inherently different standard for lesbians, whether anyone wants to acknowledge it or not? Consider this etymological attempt:

...[T]he word [Virgin] may come from her uncorrupted state, as virago, because she does not know womanly passion.

A virago is so called because she acts like a man, vir agere, that is, she does manly things and has the strength of a man. For this is the name the ancients gave to strong women. But it is not correct to call a virgin a virago if she does not perform the office of a man; nevertheless, a woman who does masculine things, like an Amazon, is rightly called a virago.