The bunny hits the big 5-0.

Christie Hefner has a picture of herself as a baby sitting on the lap of her father, Hugh, as he worked on the first issue of Playboy on his Royal typewriter. Now, this month, Playboy is turning 50 and Ms. Hefner, the chairman and CEO of Playboy Enterprises, is turning 51.

Many Playboy readers today (average age: 31) wouldn't know how to use a typewriter and would feel little connection to Marilyn Monroe, who graced that first cover.

But despite the ravages of time, Playboy remains the best-selling men's magazine in the face of competition from racy lad mags like Maxim and FHM. It's trying to use its golden anniversary "as a logical milestone for celebrating the power of the brand and the impact of Playboy on changing attitudes about leisure and play and sexiness," says Ms. Hefner.

Hugh Hefner, at 77, is still editor-in-chief of the magazine, but is concentrating on other projects, including a film based on his life. And Ms. Hefner, who joined the company in 1975 and became CEO in late 1988, is concentrating on running the company.

Having overspent in the go-go technology era, Playboy Enterprises expects to report operating income of $22 million this year and may eke out a profit for the first time since 1998. "We're feeling good about the year," Ms. Hefner says.

She brought in a new editor for the magazine, Jim Kaminsky, 40, who had been executive editor at Maxim. Newsstand sales have been up in a brutal environment. The Playboy cable channel is another piece of the empire and the biggest profit center. Playboy Online has become profitable and the company's business of licensing its brand for apparel and accessories is also a money-maker.

Is Ms. Hefner living the Playboy lifestyle? "I have an active social life with my husband but I wouldn't say it runs to lingerie parties," she quips.

Dad, meanwhile, could keep rocking for many more years. "His mother lived to 101," says the daughter. "He comes from good stock."