Face it: Some guys are simply oblivious to the pregnancy thing.

The minute two little lines appear on the pee stick, they’re thrust into a world they just don’t understand. In his book Dave Barry Turns 50, humorist Dave Barry offers this timeless advice that ought to keep newly diagnosed dads out of trouble: “You should never say anything to a woman that even remotely suggests that you think she’s pregnant, unless you can see an actual baby emerging from her at that moment.” OK, that might not be possible, but we’ve got better advice. These 18 clues to avoiding pregnancy’s biggest pitfalls should do it.

CLUE 1: Don’t say “We’re pregnant.”

You may think it shows solidarity. But because you won’t actually be play- ing hostess to a growing being in your belly—with all the accompanying aches and pains—for nine months, it’s a silly thing to say. She’s pregnant, not you. To stay in mom’s good graces however, do say “our baby” not “your baby.”

CLUE 2: Don’t touch the boobs without an engraved invitation.

Yes, they’re bigger, more sensitive, and more enticing than ever before. This is Mother Nature’s joke, because they’re no longer your playthings, dude. They’re now milk-making machines, and it hurts like hell to kick those factories into gear. Feel free to admire and suggest a romp now and again, but tread lightly. And another thing: When you sit at the obstetrician’s office surrounded by more big boobs, don’t stare.

CLUE 3: Morning sickness is real and often lasts into the afternoon and evening.

Pregnancy whips up tons of pesky symptoms. Different women get different ones on different days, and there’s no rhyme or reason for this. She also has the olfactory powers of Wonder Dog and can smell the contents of a lunchbox across the street. This is gross, causing her to wretch regularly and sometimes loudly in front of you. But don’t complain. There’s nothing much you can do to decrease her nausea except to try not to smell like anything. Just wait it out and you’ll get your toilet back sometime after the third month.

Clue 4: Pregnancy causes mood swings.

Sorry, you really can’t avoid this trap. If the mood is swinging, you’re gonna get hit. Jeff Kimes, co-author of Pregnancy Sucks for Men, explains, “Mood swings are like PMS to the nth degree. On any given day she’s sad, happy, scared, cranky—all her emotions are supersized.” It’s all due to dramatic hormonal shifts and to the fears that come with impending parent- hood. So be sympathetic and patient; these are skills that will also help you as a new dad. Kimes advises, “Don’t take mood swings personally and don’t pick fights. If a fight starts, for heaven’s sake, let her win! But don’t ever suggest she’s mad just because she has mood swings.”

CLUE 5: Pregnancy is the burp and fart Olympics, and your wife’s coming home with a medal.

Why, you wonder? Her digestive system slows way down to allow every speck of nutrition to be absorbed for the developing baby. She’ll get really constipated and gassy—and not necessarily in a cute “Oops, I burped” kind of way. This is miserable business (especially for her) and “her number-one goal will be going number two,” Kimes explains. Bigger clue: Don’t, for any comedic victory, ever mention your wife’s gaseous nature. Just keep your big mouth shut and act like you’re the guilty stinker.

Clue 6: Be careful when your wife says, “I’m pregnant.”

Kimes says, “The next words that spew from your mouth will be some of the most important words you will ever say. They’ll be rehashed at family get-togethers and repeated to her girlfriends. They must reflect how ecstatic you are and how much you love your wife. Any response like ‘Are you sure it’s mine?’ is strictly forbidden.” No joke: Women want a Hallmark commercial moment. They want violin music and a few tears wouldn’t hurt either. Already put your foot in your mouth? Remember this next time.

Clue 7: She feels lousy and deserves lots of attention.

“My husband needed blatant physical symptoms—hurling in the bathroom or fainting on the sidewalk—or he just didn’t notice,” says Kate Hodson, author of Milk It: How to Get More Than a Baby Out of the Next Nine Months. “My nausea wasn’t extreme—just a low-grade hideousness that lasted until lunchtime. But every morning, in response to my shuffling around with my head sunk between my shoulders, he would ask, ‘What’s wrong?’ And every morning I would remind him, with increasing irritation, that I was pregnant.”

Clue 8: She’s just not that into sex.

Here’s the rumor: After your wife survives the early months, she’ll be horny as the devil, with hormonally enhanced lady parts now capable of the greatest sex of her life. Peter Chianca, humor columnist for Herald Media in Boston, thinks this is pure urban myth. “A guy who’s read nothing else about pregnancy reads the chapter about the Great Second Trimester Sex Drive. Yeah, that’s not happening. I don’t know any guy who’s gotten enough to keep that myth alive.”

Even if a woman’s hormones do get her primed for action, she may not be feeling especially pretty right now. So be a smart sweetie: Take the time to give her a compliment, offer a massage, and hope for the best.

Clue 9: Ultrasounds are TV that tells you if it’s a boy or a girl.

But a word of warning: Whatever you say at this appointment could become ammunition. Don’t say the baby looks like Darth Maul. Even if it’s your fifth son—just say the right thing, like: “Another boy is perfect, my darling, for you shall be our queen.” Take note of every detail and contour; you may be quizzed on it later. Another clue: It’s very exciting when your baby kicks because it’s proof positive that something’s growing in there. Soon, your wife will ask you this one vital question: Do you want to feel the baby kick? The answer is “yes” every single time. Failure to feel the kick, with enthusiasm, will be interpreted as don’t-give-a-damn, earning you several jerk points.

Clue 10: The birth-education class is where you learn to coach your wife’s labor by reminding her to breathe.

This is a perfect arena for showing off what a supportive husband and all around good guy you are. Breathing is the first thing your wife ever learned, so you may wonder why she needs coaching. The answer is: Labor is more diffi- cult than you can imagine and breathing helps get her through. Childbirth hurts, and she’s going to need all the hands-on coaching you can muster. So breathe.

Clue 11: She doesn’t want you in her bed—and it’s not just because of the sex (see Clue 8).

Her growing belly, frequent trips to the bathroom, and backaches will make sleeping uncomfortable. And this discomfort grows throughout pregnancy. Don’t take it personally if she crowds you out with pregnancy pillows—she’s just trying to get some body support and sleep. Be content with your shrinking corner and get used to it. Later, the baby will be taking up space there, too.

Clue 12: Look alive.

In other words, pay attention to all things pregnancy, all the time. Tamara Pullman was pregnant when her husband, actor Bill Pullman, was filming Sommersby. After a 12-hour day on set, Bill would li on the floor while their Lamaze teacher taught deep relaxation. Tamara was impressed by his steady breathing until he started snoring. That baby is a preteen now. Believe me, guys, they remember this stuff.

Clue 13: Thou shall not embarrass.

Whether you’re in the ob/gyn’s office or a childbirth class, follow this rule: Unless you have something wise and supportive to say, stay mum. Nancy Grant, M.D., an obstetrician in Portland, OR, has a hefty collection of clueless dad stories: “My patient’s teacher informed the guys they may have sympathetic pregnancy symptoms. The husband asked, ‘Is that why my breasts are tender?’” What a boob!

Another cautionary tale: Before one childbirth class, Marlo Johnston warned her husband about a graphic educational film that was to be shown. “Evidently, the fact that it would be graphic mattered not to him—he was just looking forward to the movie and showed up with a freshly popped bowl of popcorn!” she recalls. “Of course this wouldn’t have mattered that much had we not been in a room full of women with varying levels of sensitivity to food smells. Needless to say, he wasn’t the star pupil that night!”

CLUE 14: Be ready by the due date.

This means you need to know what the due date is. Hodson remembers, “I had a date pretty firmly marked when I’d go into labor, experience a quantity of pain for a quantity of time, and emerge— punching the air and demanding champagne—with my very own baby. My husband, however, couldn’t grasp that it’s not some random, arbitrary date. When labor started, he was utterly unprepared, in a grumpy, turn-the-light-off-and-stop- messing-around kind of a way. He sat on the floor in disreputable underwear, vainly trying to use a faulty bicycle pump to inflate the birthing ball I’d reminded him about daily for weeks.”

CLUE 16: Don’t hog the TV in your birthing suite.

Your wife is running the show. She can watch Oprah or Grey’s Anatomy during labor if she wants. Even if the playoffs are on. So hand over the remote.

CLUE 17: No whining when your wife’s in labor.

No matter what boo-boos you’ve got, your wife’s contractions trump them. Jerome Thompson did a header on their porch stairs the day before his wife went into labor and, even with a face full of stitches and double black eyes, he had the good sense to speak not a word.

CLUE 18: Godspeed, new dad!

By this time, any guy who isn’t a blubbering idiot or utterly speechless has gotten the biggest clue of all: Your partner is amazing and you’re eternally grateful you don’t have to do any of that yourself. Now all you need is a big heads-up on the whole parenting thing.