Back in the day — and, um, which day was that, again? — the phrase "be a man" wasn't intended as some backhanded slap at gays or women, but an admonishment to grow up and stop being, well, a boy.

But in our post-counterculture age, the distinction between man and boy has been made harder to discern, both sides sliding into that ambiguous area of guyness.

If we follow the archetypes, men are supposedly stable, self-reliant and quietly strong. Boys are erratic, self-indulgent and a little too eager to prove their strength. But "guys" get to be a little bit of both.

Guys can pull six-figure incomes and still live at home with Mom and Dad. They can graduate from Ivy League schools and read nothing but video game magazines. They can stand shoulder to shoulder with their teenage children, drinking the same ice fraps, wearing the same lowrider jeans, bopping their heads to the same mp3s on their matching iPods. Be a man? Relax, just be a guy.

As interpreted by the popular media, the modern guy's inner child isn't just something to embrace but idealize. Yet isn't it revealing that our male expression of self, of guyness, is so much defined by what we admit to being, not what we aspire to?

Just as adolescence in America was extended by the mid-20th century cultural invention of the teenager, the construct of the not-man, not-boy guy has allowed for boys to "grow up" at a younger age, while at the same time keeping real social maturity at bay indefinitely.

Last year, TV critics mourned the passing of NBC's "Frasier" as the death of a "grown up" sitcom tradition that included the likes of "The Bob Newhart Show," "The Mary Tyler Moore" show and others — shows that depicted grown men and women acting their age.

What we've been left with — "The King of Queens" and its various clones — is a narrower representation of our culture's attitudes toward adulthood: grown men acting like boys.

It's been said that sports fanaticism served as a gateway to infantilism of a broader sort. KnickKnut808, who blows his paychecks buying Stephon Marbury bobbleheads off eBay, isn't seen as insane, just loyal to his team. And if you can show such loyalty to your favorite hoops team, why not to Star Wars or Kikaida or Spider-Man?

Sitting here at work in my Mets T-shirt, with my officially licensed Larry Bird figurine and a homemade Misfits bobblehead inches from my keyboard, I'm hardly in a position to cast stones.

Be a man? As soon as I'm done being a guy.