It's the first Big Talk.

Sex, drugs, driving — those more serious topics are years away. Parents first face a frank discussion about the Santa Claus issue.

(Editor's note: If you're under 10, stop reading right now.)

Some kids will have a hard time taking it all in.

Liz Fitzgerald, a Marietta mother of two, said when she and her son Brian had the Big Talk, he had a hard time believing Santa wasn't flesh and blood.

"He said, 'There is no way my parents would ever buy these things because you guys are too cheap,'" Fitzgerald recalled.

"All of the sudden he had this new appreciation for us," she said.

Most kids begin doubting the details of Christmas Eve toy delivery at age 7 or so, experts said. But that can vary widely.

"It never occurred to me to question Santa's existence until I was 10," said Rebekah Richert, an assistant professor of psychology at the University of California-Riverside, who has researched the role of imagination in child development.

The doubts, experts said, reflect the development of critical thinking as children compare tales of St. Nick with what they know of the rest of the world: How can Santa visit every kid in the world in one night when it takes us 45 minutes to get out of the mall parking lot?

Handling questions about the jolly old elf requires some finesse, especially if there are younger siblings.

"It's a really fine line between maintaining the magic of Christmas and maintaining a trusting relationship with your child," said Georgia State University psychology professor Lisa Armistead, a mother of two boys herself walking that fine line.

One handy technique, Armistead said, is rhetorical redirection. When you're asked a question like, "Is Santa real?" or "How do reindeer fly so fast?" you respond with something like, "What do you think?"

It's also a good idea to talk a bit about what Santa stands for: generosity, giving, caring for others.

But when the questions become more direct, more insistent, experts said, simply fess up.

"It doesn't always come as a complete shock," Richert said.

It's helpful to be prepared to talk about the mythology and history of Santa Claus, said Frank Farley, former president of the American Psychological Association.

"You might, for example, talk about Clement Moore," said Temple University professor Farley, referring to the poet credited with writing "A Visit from St. Nicholas," the poem that begins "'Twas the night before Christmas ..."

Few children feel betrayed by the revelation — or the years of well-intended, gobble-down-the-cookies-left-for-Santa deception that precedes it, experts said.

Still, Armistead said, it's a good idea to have an honest conversation about your motives — creating a fun, magical time.

"It's always good to give kids reasons for the decisions you make," she said.

Older siblings, parents said, get a kick out of keeping Santa alive for younger children in the family.

"I told Brian, 'Now that you have the knowledge, you're a keeper of the Christmas spirit," Fitzgerald said.

The seventh-grader happily plays along for the sake of his younger sister, writing letters to Santa.

"He being part of keeping the spirit of Christmas has brought us closer together and made it more fun," Fitzgerald said.

Armistead said her 9-year-old son enjoys "being part of the adult world," but misses, a bit, the magic of Santa, his elves and reindeer.

Earlier this month, he called a Santa hotline so that his 6-year-old brother could hear the recorded "Ho, ho,ho."

"He really wants his brother to have the magic as long as possible," Armistead said.