There are oft-shared theories about pregnancy: If you carry low, it's a boy. If you've got bad morning sickness, it's a girl.

Why it matters: There's not a lot of evidence that such gender predictors are accurate, says Tiffany Pham, OB-GYN and Flo Health medical adviser.

• Still, there's some data supporting certain boy vs. girl suspicions, Axios' Carly Mallenbaum writes.

Zoom in: Some pregnancy conditions are associated with carrying a boy or a girl — "we just don't know why," Pham says.

🤢 When it comes to nausea, studies have found that carrying a girl more often leads to severe morning sickness.

• One possible explanation is the presence of higher hCG levels — the hormone can lead to vomiting.

🤰🏼 As for belly sizes, male fetuses can grow faster, which might explain a lower, bigger belly.

• But there isn't definitive information on differences in size between male and female fetuses, Pham says.

Reality check: "The only accurate way to predict a baby's sex is through non-invasive blood tests, CVS, ultrasound and amniocentesis," says Jane van Dis, OB-GYN and assistant professor at the University of Rochester.

💭 Carly's thought bubble: As I approach my due date, I've been inundated with social media posts about boy vs. girl pregnancy symptoms.

• I've had several (unsolicited) strangers correctly guess my baby's sex — and even the fact that it's my first pregnancy.
• I posted about one such incident on Threads, and got dozens of replies from people with similar experiences. So here we are.

Go deeper.

Last week, we talked about the restorative power of water, and Finish Line readers shared their "blue mind" views. This photo comes from John Pearson in Quebec.

• "Watching the play of light on the water is a form of mindful meditation. I particularly like it when a picture can be inverted," he says.