Pregnancy myths are two-a-penny and when it comes to guessing the sex of your unborn baby there are lots of old wives tales to guide you.

However, researchers have revealed there might just be a scientific way to predict the gender – by the way a pregnant woman smells.

Scientists have found that pregnant lemurs give off a different scent depending on whether they're expecting a boy or girl. The results are the first evidence in any species that expectant mothers’ pheromones change depending on the sex of the baby.

As part of the experiment at the Duke Lemur Center in Durham, North Carolina, US, scent secretions from the genitals of 12 female ring-tailed lemurs were collected both before and during pregnancy.

Lemurs have a distinctive musky smell but the study found that when they're pregnant this scent changes – in particular when they were carrying a boy when it became more pronounced. “It’s a big change,” says Christine Drea, a professor of evolutionary anthropology at Duke University.

“When lemurs are pregnant with boys versus girls, their hormone profiles are very different,” Drea explained. 

Whether such research could be applied to humans remains to be seen. However, Drea notes that, “A woman’s scent changes when she’s pregnant from when she’s not pregnant.”