Toddlers throwing tantrums and adolescent sibling rivalry are the norm when children clamour for their mother's attention.
But when kids hit their 20s and beyond, wondering if they are mom's favourite still has repercussions that could lead to a visit to a therapist's office, according to a study by a professor at Cornell University in Ithaca, New York.
The study, which looked at 275 relationships between mothers and grown children in the Boston area, explored the link between parental favouritism and signs of depression.
"Parental differentiation among children seems to have important effects on psychological well-being - even when the children are in middle age," said Karl Pillemer, a professor of human development at Cornell.
The behavioural ramifications of parental favouritism among school-age children has been closely studied but Pillemer said investigating the link in the latter stages of family life is relatively new.
More than two-thirds of mothers interviewed showed favouritism toward one of their adult children when asked whether they had a stronger emotional bond or more conflict with a particular child.
And a whopping 90% of the adult children thought their mother had a preference for who would take care of her in old age.
Answers also crushed the notion that heightened depression was linked only to non-favoured siblings. Pillemer and co-author Jill Suitor of Purdue University found that the so-called golden children also struggled.
Favoured children often wrangle with feelings of guilt and feel obligated to care for their parents later in life, the researchers said.
Siblings who perceived favouritism from their parents also generally reported poorer quality relationships with each other, said Pillemer.
Bringing into the open that many parents do have preferences among their children is a first step to addressing some of the bad feelings associated with favouritism, he said.
But accepting that some level of parental preference is normal may be hard for families to understand.
"It doesn't mean parents don't love all their children," said Pillemer, "but that children are all different and parents relate to them differently." - (Reuters Health, June 2010)