Jan. 4, 2011 -- Elton John's recent announcement that he and partner David Furnish became fathers to a baby boy on Christmas Day caught many by surprise. But their path to parenthood -- via surrogacy -- has become an increasingly common one for celebrities.
John, 63, and Furnish, 48, reportedly consulted with another celebrity couple, Sarah Jessica Parker and Matthew Broderick, about the joys and pitfalls of surrogacy. Parker, 45, and Broderick, 48, used another woman's womb to carry their twin girls, Marion and Tabitha, born in June 2009.
More recently, actor Neil Patrick Harris, 37, and his partner David Burtka welcomed fraternal twins -- boy Gideon Scott and girl Harper Grace -- by a surrogate last October. Earlier, in July, Portuguese soccer star and international sex symbol Cristiano Ronaldo, 25, became dad to a baby boy with the help of an unnamed American woman he paid to be a surrogate.
If it seems like the number of children being born through surrogates has been growing in recent years, that's because it is. And not just for celebrity parents.
"The vast majority are regular working people," Shirley Zager, director of the Organization of Parents Through Surrogacy, a national support group, told ABCNews.com. "But celebrities bring attention in a good way to surrogacy as an option to consider among other options."
What makes surrogacy an attractive option for some is the fact that the child can be genetically related to one or both parents.
These births don't come cheap, however. Zager puts the average cost between $70,000 and $130,000.
Zager, who has been involved with surrogacy for 25 years, including the birth of her daughter in 1986, estimates that there have been about 30,000 surrogate births since 1976. And that number grows by 1,300 a year.
In addition to married couples, more gays and singles, like Ricky Martin, who had twin sons in 2008, are relying on surrogacy to have children.
The place that many celebrities turn to is the Center for Surrogate Parenting in Los Angeles. Kelsey Grammer and his soon-to-be ex-wife Camille, former "Good Morning America" host Joan Lunden and actresses Angela Bassett and Deidre Hall are former clients -- and those are just the ones who have gone public.
Surrogate Center for the Stars
"We have worked with a lot of people in the entertainment industry," program director Joanne Bubrick told ABCNews.com, including, "many high profile people no one knows about, because it's very personal."
John and Furnish went public about the help they received from the center to have their son son Zachary Jackson Levon Furnish-John.
"For many years we have talked about fulfilling one of our greatest wishes by becoming parents," John told US Weekly. "And now this wish has been granted to us, we feel so blessed and lucky."
The couple, which has been together 17 years, originally tried to adopt a 14-month-old HIV-positive boy named Lev from an orphanage in Ukraine. The country rejected their application, reportedly because of John's age and because Ukraine did not recognize their gay partnership.
Though the couple has not divulged details about how Zachary was conceived, reports have said that the surrogate was implanted with a donor egg from another woman. It's not be revealed which man -- if either -- is the biological father.
California law looks favorably upon surrogacy. Intended parents don't have to be genetically connected to the baby to be recognized as legal parents, Zager said.
"He [John] went to a surrogate-friendly state and an agency that has done this for years and years, to his credit," Zager said.
Since 1989 when they worked with their first gay couple, the center has been committed to helping same-sex couples.
"We are strong believers that they have as much right to be parents as anyone else," Bubrick said, adding, "Our work with gay couples has increased profoundly in the past 10 years as more are realizing this is a wonderful option for them."
In 1992, Hall, the "Days of Our Lives" star, was one of the first celebrities to go public about using a surrogate. She appeared in People magazine and produced and starred in a television movie based on her 20-year battle with infertility that finally ended with two successful births via a surrogate.
Most, though not all, surrogacies go smoothly, Zager said. But some celebrities have found there's a dark and worrisome side to going public about surrogates.
"The most unsavory things have been done," Parker told "Access Hollywood." "She's had her phone hacked, her personal computer information hacked, she's had threats against her and true harassment. ... She's had friends threatened and family threatened and she's had family of friends threatened.
"It keeps me up every night," added Parker, who lives in New York City. "It's really incredibly upsetting to think of her so far away and me not being able to do something, beyond what I'm legally allowed to do."