Courteney Cox has made no secret about her struggles to conceive daughter Coco.
Now, at 45, she says she's "revving up" to have her second.
"We're not trying yet. We're revving up the engines," she told OK magazine. "I'm only ready 'cause time's a-ticking. If I was 34, I'd wait another year, because I like those three-to-four gaps. I want Coco to be helping me with the next one. One child is hard. Two is probably harder."
Cox, who conceived Coco through in vitro fertilization or IVF, when she was 39, will most likely find it more difficult her second go-round.
"Forty-five is considered the dividing line," Los Angeles fertility specialist Dr. Richard Paulson told ABCNews.com.
Paulson said women 45 and older have a 5 percent chance of getting pregnant without any assistance -- and most likely they will require an egg donor.
IVF using donated eggs runs between $20,000 and $25,000, Paulson said. And if a surrogate is required, such as in the case of 44-year-old Sarah Jessica Parker, the cost can easily go up to $100,000, he said.
Forget about health insurance picking up the tab. Many policies won't cover IVF, egg donors or surrogacy.
But the financial costs are less of a concern to the rich and famous, who like Cox and Parker are willing to go to great lengths to have a child in their 40s and beyond.
"I don't like to say that these are the lengths that people go to, rather in 2009, it is good to know these options exist," said Paulson, director of the fertility program at the University of Southern California.
Apparently, Cox agrees.
"In vitro is a wonderful thing that people can do in this day and age, and I'm lucky enough to be able to afford it," Cox told Good Housekeeping.
Paulson said women as old as 50 -- and under some "extenuating circumstances," 54 -- should have the right to have children by any means if they are medically healthy.
"Children are orphaned every day in this country, and even younger moms can be run over by a bus," he said. "They can get cancer or another disease.
"I think in this country, the respect for privacy and reproductive freedom is very high," Paulson said. "I am not saying it trumps the rights of the child, but most of us think that a woman should be able to choose whether to carry a pregnancy or not."
More celebrity women are pushing off that decision until after they turn 40. Some, like Holly Hunter, who had twin boys at 47, and Geena Davis, whose twin boys were born when she was 48, refuse to divulge how they conceived their children.
Therapist Patricia Mendel, co-chair of the American Fertility Association, understands celebrities' need for privacy but said it "gives other women the image that they can have a baby at any age."
"The reality is at 47, I don't care how young you look, how much exercise, your eggs are still 47," Mendel said.
That said, Mendel said she believes egg donation is a wonderful option -- for people who have the money.
"I say to people, 'Do you have enough money?' If you don't have money, adopt. There's much more (financial) help for adoption," she said. "Some will still say, 'I'll figure it out, but I have to try this.' There's a way to hedge your bets, where you would have a better outcome."
Other celebrities are more candid about the uphill battle they faced after 40.
"Desperate Housewives" star Marcia Cross, who had twin girls at 44, told People magazine she did in vitro a week after she married husband stockbroker Tom Mahoney in 2006.
"I had already been through infertility treatments," the actress told Health magazine. "It's very, very difficult to get pregnant in your 40s. It's costly and tough on your body and your relationship."
Celine Dion also went public with her struggles to have a child with much older husband and manager Rene Angelil. After years of publicly wishing for a child, the Canadian-born singer underwent IVF treatments in New York and gave birth to son Rene-Charles in 2001, when she was 32.
In 2005, Dion openly discussed keeping another usable embryo on ice to have as a future sibling for Rene-Charles.
"I'm approaching 40 years old, and I have to tend to that," she told a French magazine. "This frozen embryo that is in New York is my child waiting to be brought to life."
Whether that's the embryo now growing inside her, Dion, now 41, is currently expecting her second child, also conceived with the help of the same Manhattan infertility specialist.
Actress Garcelle Beauvais-Nilon has been forthright about the problems she faced getting pregnant. It took five years, three miscarriages and two rounds of in vitro fertilization to conceive twin sons Jax and Jaid in October 2007.
"It's hard in every single way: emotionally, physically," she told People.
Jane Seymour also recounted for WebMD her struggles conceiving twin boys at age 44.
"I had had in vitro fertilization, and I was scanned and watched from day one," she said.
Some celebrities are even willing to push the envelope past 50, like in the case of former GMA co-host Joan Lunden and model Cheryl Tiegs. Lunden who had two sets of twins through a surrogate after turning 50, has never discussed whether she used an egg donor.
But Tiegs, who was 52 at the time, said she used her own eggs.
"When we were trying to get pregnant, I produced one perfect egg, and then when we did the one with the surrogate, I had three eggs. So I don't see why that's such an impossibility, when my system is in -- still in good working order," Tiegs told Larry King. "It's not easy. I had to have a lot of shots. But I don't see why -- it certainly is possible."
Many questioned Tiegs' claim.
"A twin pregnancy using 50-year-old eggs is a medically unprecedented event," Paulson said. "It's not impossible, but very improbable."
But like Mendel, Paulson said he believes it's up to the parents to decide how they tell the story of their child's birth.
"I want to respect people's privacy," Paulson added. "Even if it's not medically impossible, why not grant them the element of doubt they wish to have. Do we want to have that kind of thing revealed to the children before they have had a chance to hear about it from their mother?"