Beards may soon be on their way out, according to a new study from Australia's University of New South Wales. 

Researchers questioned 1,500 heterosexual and bisexual women about how attractive they found men, photographed while bearded, clean-shaven, and with stubble. There were 36 pictures of 12 men shown at three different stages of beard growth.   

When women were shown several pictures in a row of bearded men, they tended to prefer clean-shaven individuals. However, the opposite was also shown to be true -- a series of photographs of men without beards caused women to become more attracted to males with facial hair. 

Robert Brooks, who led the study, believes this may be due to an effect called "negative frequency-dependent sexual selection." This idea states that humans tend to be attracted to individuals who "stand out" from the crowd, bucking trends. 

"Whether this scales to more nuanced judgments in the more complex and varied real world remains to be seen. But it suggests that beard styles are likely to grow less attractive as they become more popular. And that innovative new styles may enjoy a premium while they are still rare," researchers wrote in a press release announcing the study. 

Beards have become highly fashionable over the last year. Facial hair has become a popular trend, especially among hipsters. In New York City, conscious-fashion men are spending up to $8,000 to fill out patchy areas on their own beards. 

"The idea is that perhaps people start copying the George Clooneys and the Joaquin Phoenixs and start wearing those beards, but then when more and more people get onto the bandwagon the value of being on the bandwagon diminishes, so that might be why we've hit 'peak beard'," Brooks told the press. 

Facial hair has come and gone out of style over the course of decades. Dwight Robinson conducted a study of pictures of men in the London Illustrated News between 1842 and 1972. Sideburns and mutton chops were the order of the day in the mid-9th century. Beards peaked in the 1890s when nine-out-of-10 men sported the feature. After the turn of the century, mustaches became fashionable. By the early 1970s, just 20 percent of men wore a beard. 

Before the 2013 baseball season, the Boston Red Sox traded away several top players, and most analysts predicted a mediocre year for the team. Instead, nearly the entire team grew beards, and the team from Beantown won the World Series. Maybe beards aren't on the way out just yet. 

Study of the attractiveness of beards was published in the journal Biology Letters.