More than 20 years after Harrison Ford hit the big screen as Indiana Jones in Raiders of the Lost Ark, the 59-year-old star is slated to reprise the role in the fourth installment of the series.

Ford will be 62 when filming begins in 2004. But whatever happened to Raiders' original leading lady, Karen Allen? Although she continues to work, her roles are mostly bit parts in films like The Perfect Storm and In the Bedroom.

While many actors seem to be cast in leading roles far past middle-age, actresses find it increasingly difficult to keep the big roles coming once they hit their 40s.

"Our cultural definition of attractiveness has been produced largely by men in the film, television and fashion industries," said Bob Thompson, a popular culture expert from Syracuse University. It shouldn't be surprising, he said, that "the Hollywood box office tends to reject women once they hit their 40s."

But according to industry observers, the attitudes in Hollywood seem to be changing.

Marcia Ross, senior vice president of casting for Disney/Buena Vista Pictures, said the independent film movement has created a bounty of new and diverse roles for actresses of all ages and is providing opportunities for women to extend their careers.

"So many different kinds of films are being made now, it has definitely prolonged the life of actresses," Ross said.

Susannah Gora, associate editor of Premiere magazine, suggested that actresses like Michelle Pfeiffer, 44, and Kim Basinger, 48, are proving that in terms of beauty and sexuality, age can be as meaningless for women as it has been for men like Ford.

"Hollywood is definitely loosening up and I think it's the incredible care that stars take of themselves," Gora said. "Women look so great and health is so trendy."

The increasing integration of women into more powerful positions in Hollywood may also be changing attitudes. Certainly, younger actresses like Julia Roberts, 34, Jennifer Connelly, 31, and Nicole Kidman, 35, will have an easier time leaping over the age hurdle than some of their predecessors.

Of course, talent can always trump age. Katharine Hepburn, for example, was nominated eight times for an Academy Award during her career that started in the 1930s. She won her first Oscar at 27 years old and her second at 75.

Glenn Close, 55, Sigourney Weaver, 52, Diane Keaton, 56, and Vanessa Redgrave, 65, have proven that Hollywood can't turn its back on women over 40 or even 50. At 67, Judi Dench's career is thriving. And Meryl Streep, often thought of as the heir to Hepburn's throne, is 52.

Although experts predict actresses like Roberts, Julianne Moore, 41, and Renee Zellweger, 33, have long careers ahead of them, they concede it may be the quality of parts, not quantity of their birthdays, that prove to be obstacles.

But insiders are predicting that the next generation of leading ladies, with their increasing box-office draw, will keep getting juicy parts from Hollywood.

"It will be fascinating to watch the career of Julia Roberts" to see how much she accomplishes, Thompson said.