(USATODAY.com) - As female movie stars get older, their compensation dips rapidly on average, unlike their male counterparts, a study says.
Female movie stars make the most money per film when they are 34 years old, but their earnings quickly decline after that age, according to a study published Wednesday in the Journal of Management Inquiry.
Male movie stars peak in their earnings per film at age 51, and their compensation steadily increases over time.
While in their 20s, female actors' compensation outpaces their male counterparts.
Researchers examined the compensation of 265 film actors and actresses who have starred in movies from 1968 to 2008.
"This is a microcosm of what happens in society," said Timothy Judge, a management professor at the University of Notre Dame and one of the study's lead authors, in an interview with USA TODAY Network.
"We are such an appearance-based society," he said, offering one theory as to why this disparity exists.
Researchers suggest roles for older female actors are limited, creating more pressure on female stars to maintain a youthful appearance.
"Men's well-worn faces are thought to convey maturity, character and experience. A woman's face, on the other hand, is valued for appearing young," according to the study.
Exceptions do exist. Meryl Streep, 64, is one of the few actresses whose star power may have grown with age.
Tina Fey joked at this year's Golden Globe Awards that Streep proved "there are still great parts in Hollywood for Meryl Streeps over 60."
Actress Jane Fonda, 76, said actresses her age must "let it be known" they want to work. "It's hard," she said in an interview in 2012 with USA TODAY.
Actor and director Clint Eastwood, 83, has also talked about the issue, saying, "Roles thin out when (actresses) get to a certain age," in an interview in 2006 with USA TODAY. "It's a crime."