19 ways to tell (or guess!) if you're having a boy or girl

Forget about waiting 40 weeks to find out the sex of your baby. Practically since the beginning of time, moms-to-be and the people who love them have come up with ways to try to figure out if that bun in the oven is a girl or a boy.

If getting a surprise in the delivery room isn’t your style, check out the following ways — scientific, traditional and downright odd — to determine whether you should break out the pink or blue.

Genetic blood test

Will it work? Yes!

While blood tests that claim to predict your baby’s sex as early as seven weeks have been around for years outside of the U.S., they’ve never been very popular here — in part because it was unclear whether they worked. But a surprising analysis of 57 studies published in the Journal of the American Medical Association shows that these tests, which detect small pieces of fetal DNA that are present in a mom’s bloodstream during pregnancy, can be between 95% and 99% accurate. Screening kits, like the Pink or Blue Early DNA Pregnancy Test, look for the presence of the male Y chromosome in a few drops of blood taken through a finger prick. If it’s there, you’re having a boy; if not, it’s a girl. (Because of this, the tests are slightly more accurate at predicting boys, since a lack of Y chromosome may mean that the male chromosome wasn’t present in the blood sample taken.)

Amniocentesis

Will it work? Yes!

This semi-invasive procedure is a slam-dunk way to know your baby's gender for sure, but because of the small risk of miscarriage your doc probably won't green-light it for curiosity alone. "An amniocentesis involves putting a needle into the fluid surrounding a baby, and then looking at the chromosomal makeup of that baby, which reveals gender as well as any chromosomal abnormalities," explains Dr. Michael Randell, an OBGYN in Atlanta. "Unless someone mislabels your results, this test is entirely accurate."

Fetal heart rate predictor

Will it work? Probably not

Generations of women swear that a quick fetal heart rate — about 140 beats per minute or above — signals girl, while below that equals boy. Why? One theory is that baby girls are supposedly smaller, thus their hearts beat faster. Dr. Randell is quick to debunk this one. "A fetal heart rate is variable and can change day to day or even beat to beat." As for theory that girls weigh less than boys, Randell says, "I've delivered plenty of 10-pound girls and 4-pound boys."

The height of your bump

Will it work? Probably not (but that won't stop strangers from guessing, anyway!)

Pregnancy is filled with old wives’ tales of unknown origins, and those gossipy ladies of yesteryear seemed especially focused on predicting the sex of that tantalizing baby bump. Case in point? Generations of women (and men, too!) swear that moms-to-be who are carrying high will pop out a girl, while carrying low means boy.

The shape of your bump

Will it work? Probably not

Feel like you’re carrying somewhere in the middle, so the height of your bump is no help? Then perhaps this is slightly different old wives tale is for you. Lore suggests that a round, ball-like baby bump means there’s a baby boy in your future, while a wider bump that kinda looks like you’re carrying all over the place is a surefire girl.

The wedding ring on a string trick

Will it work? Probably not (but fun to try!)

This test requires you to slip off your wedding ring — a needle would work too — and slip it on a string. Lie down and hold the string over your belly. If the object swings in a circular motion it's a girl; a pendulum-like motion equals boy. Don't get up too fast when it's over — this test can make a preggo dizzy!

Baby gender prediction kits

Will it work? Maybe

Products like Intelligender, a urine-based test that mixes your pee with crystals that contain certain hormones, claim you can find out the sex of your baby as early as 10 weeks — although experts including Dr. Randell are skeptical. “I’m unaware of anything produced by the baby that is somehow filtered into the mother’s urine to determine gender.” However, he says there’s no harm in trying out urine tests in pregnancy, just for fun. “Just don’t buy nursery paint color based on the results,” he warns.

Morning sickness madness

Will it work? Probably not

Were you unable to keep anything down your first trimester? According to lore, that means you're having a girl. A lack of morning sickness means you can expect a little dude. Unsurprisingly, science is not on this legend’s side. “We still don’t know exactly what causes morning sickness, but some women have an easy time with it the first pregnancy, and a terrible time with the next — even when their kids were both girls or boys,” says Dr. Randell.

Sweet vs. savory

Will it work? Probably not (so indulge your cravings)

Girls are supposed to be sugar and spice and everything nice, which is probably why it’s believed that mamas-to-be who are shoveling in the sweets are thought to be having a girl. Are you dying for French fries and a hearty steak dinner? It’s a boy. If neither seems appetizing, congrats: You’re carrying a picky eater!

RELATED: New way to predict baby's gender during pregnancy: How grossed out are you?

Chinese gender chart

Will it work? Probably not

A Chinese Gender Chart was supposedly buried in a royal tomb more than 700 years ago, but was recently discovered and is now used to determine the gender of an unborn child. (Hey, it’s a cool story if nothing else.) To use the chart, find your age at the time of conception, and then follow across to the month the baby was conceived to find the predicted gender.

Mayan gender prediction

Will it work? Probably not

Not to be outdone by the Chinese, the Mayans came up with their own method for determining boy v. girl. It’s simple: Look at the year of conception and the mother’s age at conception. If both numbers are even or odd it’s a girl. If one number is even and one number is odd, it’s a boy.

The key test

Will it work? Probably not (but an easy one to try for fun)

This test claims a pregnant woman can determine the gender of her baby by picking up a single key. If mom grabs for the key at the top round part it’s a girl, while the narrow part equals boy. What if Mom grabs the key in the middle? Twins, of course! (Warning: Do not try this test while driving!)

Ultrasound

Will it work? Most likely

Many parents-to-be choose to learn the sex of their baby at the 20-week anatomy ultrasound scan — assuming baby is in the right position. “We say that seeing a turtle is a boy and three lines is a girl,” explains Randell. (Those are the scientific terms, of course.) Just remember: This method is not foolproof. Techs can make mistakes, so it’s not unheard of to get a gender switcheroo at a later ultrasound, or at the birth itself.

Look at your hands

Will it work? Probably not (but may reveal you need a good hand lotion)

Some folks say determining your baby's gender is as simple as glancing at your hands. Dry, cracked hands mean there's a boy on the way, while soft hands signal a little girl. Although this method is certainly easy, we tend to think it's an indicator of something else — how badly you need to moisturize!

RELATED: See Kate Hudson's sweet gender reveal

Pee color

Will it work? Probably not (but a good test for whether you need to hydrate)

Let’s face it, pregnancy involves a lot of peeing into a cup, so this test couldn’t be easier. Simply take a closer look at the color to figure out what you’re having. Dark, neon-like urine supposedly equals boy, while dull, cloudy and light urine equals girl.

Feel yourself up

Will it work? Probably not (though a fun test for you and your partner to try!)

Pregnancy involves a lot of boob changes, and yet another old wives’ tale says those growing milkers can clue you in to gender. Grab hold of your honkers and see which one feels bigger. A larger left breast supposedly means boy; a larger right one a girl. Want to make this test more fun? Ask your partner to do it for you!

The pimple test

Will it work? Probably not

Pregnancy or not, acne is no fun, but some say those annoying red marks could unlock the gender mystery. What does your skin look like during pregnancy? If you have maintained your clear-faced glow, then bring on the blue. Lots of spots equals girl.

The state of your face

Will it work? Probably not

As the legend goes, moms-to-be who have kept their looks can expect a boy, while preggos who have “lost their looks” (so sad!) are having a girl. Why? The belief is the little girl has stolen Mommy’s beauty! That’s both adorable and depressing at the same time.

The way you snooze

Will it work? Probably not (so enjoy a stress-free sleep)

Next time you wake up in the morning, remember to check which way you’re resting — and yes, we do realize the simple act of sleeping during pregnancy is no easy task. As the myth goes, if you sleep on your left side it’s a boy. Right side equals girl. So write a big note on your alarm clock, or better yet, ask your partner to check for you while you catch a few extra zzzs.

A version of this story originally appeared on iVillage. TODAY.com first published this story on October 28, 2013.