Twins are taking over! These days, around 32 out of every 1,000 babies born in the U.S. are twins, according to the Centers for Disease Control and Prevention. Back in 1980, only about 19 in every 1,000 newborns had twin status. 

What’s not surprising: Twin newborns can be a challenge. But once you’re over the two-tiny-babies-at-once hump, raising them can actually be easier than having kids of different ages. Read on for more twin eye-openers.

There are more than two types of twins

Think there are only fraternal and identical twins? While those are certainly the most common, there are actually other types of twin babies. You could have mirror image twins, for example — identical twins from an egg that has split into two later than usual — who have "mirror image" birthmarks and traits (the same ones but on opposite sides).

In very, very rare cases, your twins may be conceived through superfetation, when eggs from two separate menstrual cycles are released, fertilized and then implant in the uterus. These twin babies may be born on different days — and sometimes even weeks or months apart.

Your fraternal twins might really be identical

Fifteen percent of parents were mistakenly told that their identical twins were fraternal, according to a University College London study. Why the confusion? Most identical twins share one amniotic sac and one placenta, but 25 to 30 percent actually have two separate placentas and amniotic sacs.

However, not all doctors are aware of that fact, according to a survey of American College of Obstetricians and Gynecologists (ACOG) members.

If you’ve got same-sex fraternal twins who look an awful lot alike, there’s a chance they might be identical. Talk to your doctor about a DNA test if you’re curious enough to find out for sure.

They will have physical differences, even if they are identical

Can’t tell a pair of identical twins apart? Print ’em!

Despite having nearly matching DNA, the pattern of skin grooves and ridges on their fingers is not the same. Fingerprints are believed to be affected by each baby’s bone growth and contact with amniotic fluid in utero — so while they’re likely very similar, their fingerprints will never be exactly the same (unlike, say, their cowlick or dimples).

Twins bond before they’re born

Three-dimensional ultrasound images of twins in utero have shown that the fetuses seem to reach for each other intentionally and (aw!) stroke each other as early as 18 weeks. If you've got multiples, try to remember their prenatal chumminess the next time they’re tearing each other’s hair out. Yes, twins fight — but they also seem to be hardwired to connect.

You will likely give birth to twins early

With so many mamas having twin babies these days, it may seem like being pregnant with two is no big deal. And while it's safer and easier than ever to have twins now, it's still quite a feat to carry a pair of babies at the same time.

Women expecting twins are more likely to give birth early (more than 60 percent of twins are born prematurely), with the average twin pregnancy lasting 35 weeks. That’s not to say your little duo won’t be perfectly healthy, but you will get some extra monitoring throughout your pregnancy, and your newborns may need to spend some time in the neonatal intensive care unit (NICU) if they’re born weighing less than 5 pounds.

It’s a good idea to have your hospital bag ready to go by 28 weeks, and drop hints that your baby shower should be scheduled sooner rather than later.

Twins can sometimes talk in tongues

About 40 percent of twins actually develop their own language, according to researchers. When twins mimic each other’s babbles instead of their parents’ speech, it’s called idioglossia or cryptophasia. 

Twins often look to each other as language models and assign meaning to those jabbers. So, “pfft!” could mean “let’s go!” to your tiny twosome. Don’t worry, their twin-speak won’t hinder their actual language development (most twins drop the secret speech as their real vocabulary expands), but it sure is cute while it lasts!

Twins can

affect each other’s sleep for years

When they’re babies, their middle-of-the-night hunger cries will wake each other up (and even if they don’t, you’ll probably rouse the sleeping twin when the other wakes up to eat). 

Even as older kids, even if one twin is bone-tired, she likely won’t go to bed if the other one is awake because she doesn't want to miss out on anything her twin may be experiencing. 

Raising twins gets easier

Having two little ones at once gets smoother later, so hang on through those tricky early days. One upside: Parents with kids of different ages have to plan their days around multiple nap schedules and bedtimes, so having two on the same sleep routine is one of the few ways twins can be easier!

When they're a bit older, chances are your same-age siblings will turn into built-in best friends who are able to play together and comfort each other. What's more, you can put them in school, camp and some extracurricular activities together (depending on their interests) without having to shuttle between programs suited for different ages.

Also, they’ll likely be interested in the same types of shows and movies, eliminating some of those TV time battles, and you’ll ideally just have one bedtime to navigate.

Competition between twins isn't always bad

When you have two kids the exact same age in one family, competition is inevitable. And sometimes, that’s a good thing.

One twin might be more motivated to give walking a try when he sees his brother cruising around. When you’re potty training, a race to do away with the diapers can make the process shorter for twins.

Still, too much competition isn’t healthy. Try to avoid comparing your kids and emphasize each twin’s unique strengths. And spend one-on-one time with each of them whenever you can to nurture their individuality and independence.

Twins can develop very differently 

As a parent of twins, you'll gain a unique perspective on the nature versus nurture debate.

Though you started them both on the same solid foods, for instance, one tot may end up the pickiest eater on the planet while the other will try anything and everything. You've been reading them the same bedtime stories and playing the same games with them all along, but while one might turn into a little bookworm, the other could prefer building with blocks over reading.

You may realize sooner than other parents that you can’t take too much credit for your kids’ personalities, development, behavior and interests — or too much blame, either!