These seemingly innocent habits could be adding up to some serious below-the-belt trouble

You spent so many years trying not to get her pregnant, so when you finally want to become a dad, you might be surprised to discover that conceiving isn’t as easy as you may have thought. In fact, 1 in 8 couples have trouble getting pregnant. And in 1 out of every 3 cases, the problem is on the guy’s end, according to the national fertility organisation Resolve.

“Normal sperm counts have declined in the last several decades,” says Ajay Nangia, M.B.B.S., a professor of urology at the University of Kansas Medical Center specialising in male infertility.

Part of that dip could be due to seemingly harmless things guys do on an everyday basis. Here, 7 common habits that might be messing with your sperm.

1. STAYING UP TOO LATE
Turn off Netflix and get to bed: Guys who logged less than 6 hours of sleep per night were 31 percent less likely to get their partners pregnant than guys who slept for 7 to 8 hours per night, according to a preliminary study in the journal Fertility & Sterility.

Lack of sleep may lower your production of the hormone testosterone, which is essential for sperm production, researchers say.

But too much shuteye isn’t the answer, either: Men who snoozed for more than 9 hours a night also demonstrated lower levels of fertility. So shoot for 7 to 8 hours a night—the sweet spot in the study.

2. USING THE WRONG LUBE
Popular commercial lubes like K-Y and Astroglide can hamper your sperm’s motility, or their ability to efficiently swim towards the egg to fertilise it, a 2014 study in Fertility & Sterility found. The lubes’ thick consistency may make it difficult for the sperm to move, says Dr. Nangia.

“They’re fine for intercourse [when you’re not trying to get pregnant], but they can act a bit like a spermicidal barrier,” he says. (Still, you should never use a lubricant as birth control.)

Plus, they also contain hydrochloric acid, a preservative that can kill sperm, he says.

Instead, stick with a fertility-friendly lube like PreSeed, which is less damaging to sperm, the study found.

3. SKIMPING ON FISH
Ordering your fair share of fish might save your swimmers. When Harvard researchers studied the diet and semen quality of 155 men, they found that guys who ate the most fish—particularly omega-3-rich fish like salmon or tuna—had higher sperm counts and higher levels of normal, healthy sperm than those who ate less.

On the flip side, men who ate the most processed meat, like bacon, hotdogs, and salami, had the lowest sperm counts and the highest levels of abnormally shaped sperm compared to men who ate the least.

Processed meats might decrease reproductive hormones like testosterone, while the omega-3 fatty acids in fish promote the formation of healthier sperm, researchers say.

4. GUZZLING SODA
Guys who drink more than one sugary soda a day have lower sperm motility than those who rarely or never sip the sweet stuff, a study published in Human Reproduction found.

Eating or drinking too much sugar can lead to insulin resistance, a condition where your cells are unable to take glucose from your blood and use it for energy. This can lead to inflammation, which can hinder how your sperm moves, the researchers say.

Plus, if your soda habit is making you fat, that could pose its own problem. Too much fat prompts your body to pump out less testosterone and more oestrogen, which is bad for your fertility, Dr. Nangia says.

Extra fat tissue around your thighs and groin can also raise the temperature inside your scrotum. That could create a too-warm environment that’s also bad for your sperm, he says.

5. STRESSING OUT
Men with higher levels of perceived stress have worse sperm quality than men who report feeling less stressed, a study from Columbia University found. Too much stress might throw your reproductive hormones out of whack, or lead to the creation of inflammatory proteins that hurt sperm, Dr. Nangia says.

No matter what’s eating at you, find ways to keep your worries from getting out of control—like talking with your partner, making time to exercise, or looping in a pro if your stress remains sky-high, suggests Dr. Nangia.

6. KEEPING YOUR SMARTPHONE IN YOUR PANTS POCKET
Cell phone exposure may hurt the way your sperm move and decrease the number that are swimming around, a recent British review of 10 studies concluded. The radiation emitted from phones could cause DNA damage to sperm. And the heat from a phone could raise the temperature inside your scrotum and hamper sperm production, researchers say.

Does that mean you need to ditch your device altogether? Probably not, Dr. Nangia says. But if you’re concerned, talk with your doctor. If you have your phone in your pocket all day, every day, it might be worth finding ways to reduce your exposure, like sticking your phone in your jacket pocket.

7. DRINKING TOO MUCH
An occasional beer or glass of wine with dinner isn’t a big deal. But research has linked heavier drinking to lower testosterone levels, lower sperm counts, and smaller numbers of healthy sperm.

Drinking 25 or more drinks per week is linked to a significant decline in sperm quality, one Danish study found. And guys who downed 40 drinks per week had 33 percent lower sperm counts and 51 percent less healthy sperm than those who drank only 1 to 5 drinks a week.

“Alcohol is a toxin,” Dr. Nangia says. And your brain isn’t the only thing it hurts—alcohol can also lower your testosterone levels, which can hurt your sperm production.

If you think that your drinking might be affecting your fertility, talk with your doctor. Together, you can come up with a plan to cut back.