Many moms know it. Few dads are willing to admit it.

But when push comes to shove, moms are more likely than dads to play the bad guy when it comes to disciplining a child, says Dr. Carin Rubenstein."It's always been that way," adds Rubenstein, a social psychologist from North Tarrytown, N.Y. "The old threat `Wait until your father gets home' rarely worked years ago and rarely works today. Only one in 10 moms even bothers to threaten her child with that old standby."

Out of a total of 4,500 females who responded to a Parenting magazine survey "Who's Really in Charge?" conducted by Rubenstein, 80 percent said they bore the brunt of the disciplining burden at home. The remaining 1,500 survey respondents were men.

The average age of the female respondent was 30 and the average male respondent 33. The average respondents' oldest child was about 4 years old.

Some of the highlights of the survey, published in the March issue:

- The majority of mothers and fathers said that although their own parents usually put them across their knee, they themselves tend to reason with their children and give them

timeouts. That is, they remove a misbehaving child to a quiet spot to cool down.

- Six in 10 moms spanked their children at least once every few months, but even more - nine in 10 - gave timeouts.

- Women who had their first child after the age of 29 were more patient and consistent in disciplining their children, and less likely to spank, than younger moms.

One of the reasons moms are the main disciplinarians is that they spend more time with the children. "When children disobey or fight, Mom is usually there.

"Even if both parents work, there's the tendency to allow the mother to do the disciplining when she gets home.

"When dads come home, they don't want to deal with any unpleasantness. They'd rather bribe the child with a treat than to face and deal with the problem."

In reality, 67 percent of the moms in the survey said they're the ones who scream and yell at the kids, compared with 55 percent of the dads, and 42 percent of the moms spank, compared to 37 percent of the fathers.

When it comes to spanking, the majority of parents draw the line at spanking by anyone other than themselves. Teachers, friends' parents and caregivers all get the big thumbs-down.

More than half the fathers who answered the survey admitted to plying their kids with bribes of ice cream or other treats in a one-week time.

The survey also showed that parents today are even-handed in their disciplinary style. Three-quarters say they generally agree with their partners on matters of discipline, and they enforce the same rules for boys, girls and only children.

"Many parents tend to swing," Rubenstein says. "They're not sure what is the right way to discipline. With many it's whatever works."