More than 84% of parents admit to lying to their kids at least once a month, according to a Redbook survey of parents. (The magazine issue hits newsstands Feb. 24)

Just once a month? I can't keep track of the lies that come out of my mouth when it comes to my nearly 2-year-old.

This weekend, I told her that the Tic Tac box and the enclosed white capsules were a music box with white musical beads. "Shake it!," I instructed her. And she did with a little bop of her head.

Alaska Gov. Sarah Palin describes in her new biography how she lied to her children about being pregnant -- even in the face of the searing evidence of an ultrasound photo.

But where does a parent draw the line?

Many of us have agreed that white lies (Tic Tacs are musical instrument/Santa is real) are OK.

But where is the demarcation? How many lies account for a false sense of hope, security, trust in our kids?

MSNBC.com broached this subject last year. Here's what one psychologist they talked to said:

"It depends what you're lying about," says Victoria Talwar, who studies children and lying. "The answer in many cases is that lies are not necessary."

The risk with too many lies, though, is that over time they can erode the trust a child, particularly a perceptive teen, has in a parent, Talwar cautions. And serious untruths, such as not disclosing an adoption, for instance, can be devastating. "We really feel betrayed when someone lies to us, especially someone close to us," she says.

Where do you draw the line?