There are a plethora of old wives tales that promise to predict whether or not you’ll conceive a male or female child, but science has long taught that a baby’s gender is completely up to chance. However, new research has suggested that there may be more factors at play when it comes to determining a child’s sex — researchers discovered that a woman’s blood pressure at the time of conception can influence her child's gender.

The study determined that women who had boys tended to have higher blood pressure prior to pregnancy (106 mmHg) than women who had girls (103 mmHg), according to The Independent. However, it is still unclear whether women can choose a gender purposely by matching blood pressure with conception time.

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“What we asked here was, ‘Were there physiologic characteristics of the mother prior to the pregnancy that related to her likelihood of having a boy or girl?’” study author Dr. Ravi Retnakaran, told The Huffington Post.

“The only thing that was related was blood pressure but blood pressure was strongly related.”

For the study, the team took the blood pressure of a group of 1,411 women in Liuyang China who were planning to get pregnant. Other factors such as the women’s age, whether they smoked, their weight, and cholesterol were all also taken into account, but the only factor that seemed to matter was their blood pressure. The preconception blood pressure of women who birthed males was about 2.6 percent higher than those who birthed males.

Although the findings are interesting, the researchers stress that they do not want people to try and manipulate their blood pressure in an effort to give birth to a certain gender.

“We don’t believe it’s cause and effect. We think it’s a marker of the underlying physiology,” explained Retnakaran.

Source: Retnakaran R, Wen SW, Tan H, et al. Maternal Blood Pressure Before Pregnancy and Sex of the Baby: A Prospective Preconception Cohort Study. American Journal of Hypertension . 2017

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