What Is the Ring Test for Gender?

A 2012 study in the Netherlands found that 69% of pregnant people wanted to know the sex of the fetus before birth; a similar study in the United States published in 2004 found 58% of expectant parents either knew or planned to find out the unborn baby's sex before delivery.

And while science can determine a baby's sex in utero as soon as 10 weeks into a pregnancy, old wives' tales that have been passed down through generations tell parents-to-be how to guess the gender even sooner. Some people swear by these gender prediction methods despite lacking scientific evidence, and some just do them for fun.

To perform the ring test, also known as the string test, take a ring that belongs to the pregnant person (a wedding ring, for instance) and tie it to a thread or string. Have the pregnant person lie down and let someone else (such as a family member) dangle the ring over the baby bump.

According to the ring test, the baby will be female if the ring moves in a circle. The baby will be male if the ring swings back and forth in a straight line. Then again, as with many folktales, some people say the exact opposite: If the ring swings in a circle, it means the baby is a boy, and if it swings back and forth, it's a girl.

Of course, there is no scientific method to determine the sex of an unborn baby other than working with an obstetrician.

Can the ring test still be accurate if there's no scientific basis for this old wives' tale?

Researchers at Johns Hopkins Bloomberg School of Public Health wanted to find out, too. In 1999, they asked 104 pregnant people to predict the sex of their unborn babies, using whatever method they preferred — the ring test, dreams or any other hunch.

The people studied had a 55 percent success rate, about the same as taking a wild guess. So it seems the ring test, and others like it, can't predict a baby's gender any better than flipping a coin.

But like all superstitions or folklore, our brains want to believe. Engaging in superstitious behavior can provide a sense of control. The person holding the string may wish for a girl, so they begin swinging the ring in circles using subtle muscle movements. If their gender predictions come true, they may pass the method to others.

The wedding ring gender test has its roots in pendulum-assisted divination. For hundreds — if not thousands — of years, people have tied weights to strings to create pendulums and interpreted their gentle swing to answer life’s big questions.

According to a 1697 British text, the ancient Greeks "fill'd a Bowl with Water, and let down into it a Ring, equally poised on each side and hanging by a Thread tied to one of the Fingers: then in a form of Prayer requested of the Gods to declare, or confirm the Question in dispute; where upon, if the thing proposed was true, the Ring of its own accord would strike against the side of the Bowl a set number of Times."