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The best ways to tell the sex of your baby — how accurate are they?

Baby boys, baby girls — both genders are sweet as pie. You may have not have a preference when it comes to your child’s gender, but that doesn’t mean you aren’t intensely curious starting the second after you get a positive result on that pregnancy test. All gender-reveal methods aren’t created equal, of course, so we rounded up some of the most trusted and interesting of the bunch, as well as a few wild-card ways that some people swear you can actually influence your baby’s sex at conception.

From invasive tests that will make you squirm to think about them, to good old-fashioned links between nausea, pickle cravings and gender, here are 11 ways you can tell the sex of your baby and how much faith you should have in them.

Image: Design: Terese Condella/SheKnows; Image: Getty Images

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1. Chorionic villi sampling

Chorionic villi sampling is one of two invasive tests that learn the chromosomes, or gender, of your baby, says Dr. Sherry Ross, OB/GYN and Women’s Health Expert at Providence Saint John’s Health Center. “(CVS) is done between 11-14 weeks and involves a needle that is inserted through the vagina or uterus under ultrasound guidance to collect cells from the placenta,” Ross says. “The placental tissue removed is tested for chromosomal analysis.” The objective of the test is to diagnose chromosomal abnormalities like Down syndrome in women if there’s a family history of genetic and chromosomal problems or if the mom-to-be is 35 and older. The test is performed in the first trimester and there are small, but very serious risks associated with invasive testing, says Dr. Sarah Yamaguchi, OB/GYN at Good Samaritan Hospital in Los Angeles. The accuracy rate with CVS is close to 100 percent.

2. Amniocentesis

An amniocentesis (also called an amnio) is sampling of the fluid around the baby done in the second trimester, usually after at least 15 weeks, Yamaguchi says. “It is close to 100 percent accurate, as it is a test of the cells from the pregnancy,” she says. “The risks are minimal, but can be severe. There is a small risk of miscarriage or fetal injury.” Other risks Ross cites include amniotic fluid leaking, infection, needle injury to the baby and Rh sensitization occurring less than 1 percent of the time. Like CVS, an amnio is traditionally offered to women who are over 35 or who are high-risk for chromosomal abnormalities.

More: You’re darn right I ate my placenta!

3. Non-invasive prenatal testing

This new test, which Ross describes as the “popular kid on the block,” is both non-invasive and takes maternal blood to determine chromosomal abnormalities and gender as early as 10 weeks. “The NIPT is cost effective, no risk to the baby and has a 98 percent to 99 percent accuracy rate,” Ross says. “Pregnant women of all ages, high- and low-risk, are interested in learning as much as they possibly can about the health and gender of their unborn baby, especially with non-invasive testing.” During NIPT, fetal DNA, which is circulating in the blood of the mom, is extracted from the blood of the mom and tested for the presence of a Y chromosome, Yamaguchi explains. If it is present, then it is a boy. “This is not as accurate as invasive sampling, but almost as accurate,” Yamaguchi says.”

4. Ultrasound

Out of all of the in-office tests a pregnant woman can rely on to find out the gender of her baby, the ultrasound scored lowest on the list for both Ross and Yamaguchi. “Ultrasound has been around since the 1960s and is generally safe, since this form of acoustic energy [uses] sound waves so no radiation is used,” Ross says. “There is heat generated by these sound waves and excessive exposure may lead to tissue damage, but more studies are needed to know how this affects the baby and the mother. Ultrasound can be used to check the baby’s anatomy and size, check the placenta location and also determine gender. The best time to perform the ultrasound to determine gender is between 18 and 22 weeks. The accuracy rate will be completely dependent on the ultrasound experience of the doctor or ultrasound technician performing the scan. Ultrasounds during pregnancy should only be doctor-recommend.”

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Yamaguchi says doctors look for either labia or testicles and penis (commonly referred to as the “hamburger sign” or the “hot dog sign”). She agrees that the accuracy of fetal gender depends on who is doing the ultrasound. “A general OB/GYN is able to see the sex of the baby with fairly good accuracy, but is likely not as accurate as a perinatologist who does detailed anatomy scans and has years more training in fetal ultrasound,” Yamaguchi says.

5. The “squeamish” test

Polish researchers at the University of Wroclaw in Poland recently discovered that most of the 92 pregnant female subjects they questioned who were carrying boys reportedly shared one thing in common: They felt “squeamish” and experienced far more feelings of “disgust” than women carrying girls. Not to be confused with pregnancy nausea, this squeamishness may be a way for mothers to protect their male embryos, which other studies have found are more vulnerable than growing female embryos. What do experts think? Both Ross and Yamaguchi are skeptical.

“It’s great to see researchers looking at different emotional reactions affecting pregnant women to see if there is any relevance in predicting gender that doesn’t involve the usual channels traditionally used,” Ross says. “However, until more extensive and valid studies are performed, I would not bank quite yet on emotional reactions such as ‘squeamishness’ being a definitive prognosticator of the baby’s sex.”

6. Gender prediction kits

You’ve seen scores of them in drugstore and you’ve probably wondered about their accuracy. Gender prediction tests, many of which swear they can tell you the sex of your baby in as early as six weeks and can be performed in the privacy of your bathroom, are alluring because they’re affordable and satisfy our curious minds. But many experts say the science behind them is faulty. After peeing in a cup, the test purportedly searches for traces of testosterone (proving you’re carrying a boy) and your urine changes color to reflect the baby’s gender. But experts say six weeks is still far too early to find chemical changes in urine as a result of testosterone.

Pricier gender kits actually involve taking your blood sample and sending it to a lab — but again, doctors warn that there’s a difference between testing your own blood at home at such an early stage of your pregnancy and having it done in a lab. The bottom line is: Think twice before shelling out the money for these kits.

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7. Pop an aspirin

A recent study shows that women with a history of miscarriages who take aspirin around the time they have sex and conceive a child increase their likelihood of having a boy by one third. Because male embryos are more vulnerable than females, inflammation in the womb reportedly decreases, thanks to the aspirin, and there’s less of a chance that the immune system sees an embryo as a foreign body it has to attack. It’s an interesting and novel concept that still likely requires more research to prove its accuracy, but the findings — 31 percent of the women in the studies who took aspirin had a boy — are definitely interesting.

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