Be honest: Have you ever wondered if your mother has a favorite child --and it's not you?

It's an uncomfortable question. A mother might tell her children she loves them all equally --and maybe that's true. But kids are sensitive, and are not easily fooled.

From my own experience growing up with an older sister and younger brother --and having raised two of my own kids, a son and a daughter --I've learned that children are very sensitive to what their parents think of them (even if what they assume about their parents' feelings towards them isn't always correct.)

Observing how their parents treat them and their siblings, especially over several years, helps children form an internal narrative around how their parents feel about them and their brothers and sisters. Depending on how the narrative plays out --even in an adult child's mind-- it can be a source of confidence and happiness. It can also be the source of insecurity and anxiety. 

It's a topic two academics have been closely studying for the past two decades. Jill Suitor, a sociology professor at Purdue University, and Karl Pillemer, a professor at Cornell University, conducted face-to-face interviews with 556 Boston-area mothers between the ages of 65 and 75. They asked them a series of questions including "Which of your children are you most likely to talk to about a personal problem?"; "Which child would you most want to be your caretaker as you age or if you were to get sick?"; "Which child are you most proud of?", and "Which child has disappointed you the most?"

They also directly posed the question at the heart of their inquiry: "Do you have a favorite child?"

And what did they learn? Moms do have a favorite child. In general, "daughters were overwhelmingly chosen over sons," says Suitor. Lastborns were also selected more frequently than first or middle children. 

The researchers also wondered if a mother's responses would match up with her children's. Before conducting their interviews, Suitor and Pillemer guessed that the kids who were the most confident in their choice would be the most accurate, but that didn't turn out to be true. "Kids are really bad reporters when it comes to who Mom is proud of," Suitor says. "Only 39 percent were correct, and the kids who were not chosen tended to be the most sure they were Mom's favorite." 

Seven years after their original interviews, Suitor and Pillemer followed up with their group of respondents and learned that mom's favorite did not really change over time. "Much to our surprise, most of the moms named the same children in response to each of these questions that they'd given us seven to eight years before," Suitor says.

These findings are backed up by another recent study in the Journal of Consumer Psychology that suggests that a mother would have a high likelihood of buying something for her daughter, while a father would choose a gift for his son. "While more than 90 percent of people in the study said they treat children of different genders equally, researchers discovered that most parents unwittingly favor the child of the same sex when it comes to spending money," according to ScienceDaily, a website that covers news about recent research.

"We found that the effect was very robust in four different experiments and across cultures," says researcher Kristina Durante, an associate professor of marketing at Rutgers Business School in New Jersey. "The bias toward investing in same-gendered children occurs because women identify more with and see themselves in their daughters, and the same goes for men and sons."

So, what should you do with all this information? Turn to your siblings, suggests Suitor, and try not to worry about who's the favorite. "Siblings can be a source of friendship and closeness and support throughout your life," she says, "but only if those relationships haven't been undermined by rivalry."

Watch Jill Suitor discuss her research in this TEDx Talk: