I am thinking about buying stock in the Kimberly-Clark Corp. (NYSE: KMB).

Not that they need my meager investment. In January, the company reported a 7.4 percent increase in net sales for the fourth quarter of 2006 to a new quarterly high of $4.3 billion. The reason for such record-breaking gains? Huggies diapers and Depends incontinence care products.

Memo to Kimberly-Clark: You ain’t seen nothin’ yet.

It’s been a week and a half since Lisa Nowak, astronaut and woman-on-a-mission (and I don’t mean to Mars), donned an MAP (Maximum Absorption Garment) to expedite her 900-mile trip from Houston to Orlando. Her alleged objective: to kill her rival in a love triangle drama whose theme song should be “NASA’s Gone Funky.”

Since then, I have heard no less than five people give serious and thoughtful consideration to the idea of wearing diapers on long road trips.

Needless to say, all of these people were men.

“I’ll bet we could trim an hour, minimum, off our trip to the lake,” one of them said.

“Makes that trip over the Rockies look like a cakewalk!” said another (who happened to be my own father).

Apparently, these guys can see nothing wrong with sitting for hours in a pair of soggy underpants made of plastic and pulp, as long as their No. 1 objective can be achieved: making good time.

In my 51 years on this planet, I have learned that when a man climbs behind the wheel, he becomes hopelessly engaged in a game of “Beat the Clock.” Whether it’s a cross-country journey or a hop across town, the all-consuming goal is to get there in “good time.”

“Good time” is a subjective term that usually means “faster than last time.”

Men will go to any lengths to make good time, including restricting rest stops to a minute and a half, exceeding speed limits by upward of 20 miles per hour, and purchasing expensive radar detectors to avoid getting stopped by the highway patrol. (It’s not the speeding ticket men fear; it’s the accompanying 10-minute delay.)

Evidently, we can now add “wearing diapers” to the list.

Have you ever heard a man threaten his young children, squabbling in the backseat, with “don’t make me stop this car?” Ninety-nine percent of the time, this statement is an idle threat. Because the last thing a man wants to do is pull over, jeopardize his “good time” and delay arrival at his destination, thereby forfeiting bragging rights until next year’s vacation.

“Yep. We made it in seven hours flat. Last year, it was 7:48. Must be the diapers …”

But, wait, you say. This astronaut is a woman! The mad obsession with making “good time” can’t be a man’s exclusive domain.

OK, sure. I will admit to the occasional attack of “lead foot” while driving our nation’s highways during the summer. It’s difficult to resist the temptation when you’re in vacation mode, especially when a poolside cocktail awaits you at the end of the road.

It’s easy to get caught up in the race when the man you’re traveling with is hell-bent on breaking the sound barrier with your minivan. Suddenly, achieving “good time” becomes a team effort, a family project causing parents to scream uncontrollably at roadside gas stations: “C’mon, kids! Put those road maps down. Back in the car! Run! RUN!!”

But, diapers?!

Sorry. That’s where we girls draw the line.

First of all, a garment that adds padding below the waist is NEVER going to fly.

Secondly, any woman worth her salt in the hygiene department would insist on stopping just as frequently to CHANGE her diaper. Why do you think landfills are overflowing with nonbiodegradable Pampers? Because moms can’t bear the thought of their precious little babies’ behinds chafing in mushy nappies. Don’t you think women would have the same consideration for their own tushes?

Third, and most importantly, making “good time” is not a do-or-die proposition for us. Women have our priorities in check. So what if we’re a little late checking in at the motel? That antique store (right next to the interstate outlet mall) is worth every minute of delay.

OK. So maybe I won’t buy shares in Kimberly-Clark, after all.

But mark my words: The next time you see a bunch of guys headed west with skis on the top of their car, I’ll give you 10-to-1 odds there’s a case of Depends in the trunk.