I’ve seen men of panache and vigor turn into mushy-minded slobs at the birth of a baby.

Granted, you have to sacrifice a lot to be a dad. I’m not disputing that. My wife has taught pre-school for a decade — enough years to impart how difficult child-rearing can be. That’s why I find it strange that doting young fathers seem to have such overt sex appeal.

At a recent weekday lunch, my boss — an extremely level-headed woman — could not take her eyes off of a guy cooing and ahhing over his newborn. When my wife learned that Lenny Kravitz has a tattoo on his arm of the first picture drawn by his daughter, I thought the swooning would reach Depp-level proportions.

Fatherhood seems to transform men in the eyes of women. Mean-spirited bastards become lambs simply because they know how to hold a bottle. True losers transform into pillars of the community as they suddenly become passionate about where sex offenders live.

So I asked a friend of mine who works as a leadership consultant and psychologist, about the reaction he gets when holding his infant girl. I wanted to know if devotion to his brood puts ladies in the mood. He spoke of an “evolution” in female yearning.

“It used to be the man in authoritative uniform that made a woman weak at the knees, but now it is the man who gently cradles an infant, protecting it from danger, like a regal lion standing guard over his cubs,” he said. “I have experienced the adoring gaze of the female many times, but never so intensely as when carrying my daughter in the fresh produce section of the supermarket.”

Christopher Maples, 31, executive director of Dads Inc. of Indiana, a nonprofit organization that works to build strong father-child bonds, speculated that the reason may be a contented Zen exuded by new dads.

“It’s probably that we’re not looking,” Maples said. “We have kids and wives, so I don’t think we’re coming off as desperate or trying to get with someone, because our lives are full.”

Indy.com user diana_leigh suggested that many women adore a new father for the commitment he is displaying — like a wedding ring effect on steroids. “They see him as maternal — really! He can tend after his flock and be warm and nurturing,” she wrote. “It’s basically emotional porn for women.”

But then again, it could be that the guys are fooling themselves. Indy.com’s Amy Bartner imagines the baby is the draw — not the boy holding it lovingly in his arms. In this world view, pushing a baby in a stroller is like walking a golden retriever.

My friend (who also happens to own a golden retriever) agrees that the attraction could be fool’s gold. And he also notes that the attention is fleeting.

“It seems that as the child grows to become less vulnerable, so the male guardian becomes less attractive,” he said, like some anthropology minor. “The moral of this story is to enjoy it while it lasts.”

Do new fathers exude some major sex appeal?

Christopher Maples, the 31-year-old father of 3-year-old Jackson, and 3-month-old Luke, and also executive director of Dads Inc. of Indiana, believes young fathers do benefit from an infant in their arms. “But I think it starts with marriage, when you see that we’re capable of commitment and being serious with our lives, especially in this age range. Rather than coming across as someone who wants to hang out and drink beer with your buddies and play Nintendo, you’re being mature and looking forward to greater things in life.”

By contrast, indy.comer diana_leigh, a 25-year-old unmarried woman, said she doesn’t find young fathers attractive at all. “Mostly because I see it as the final nail in the coffin. Not only is the dude in question way WAY off the market, he’s basically damaged goods. From now on, he’s a dad, and he always has ties to whoever he made the babies with. I don’t mean this in a bad way. I just mean that I can’t swoon over a guy who’s a dad. He ceases to be a flesh-and-blood man anymore. He’s just a father now. It’s commitment, it’s final, it’s permanent. Not so sexy.”