If your parents have told you that they love you and your siblings equally - research says maybe not.
Sociologist Katherine Conger put 384 adolescents under the microscope to find out if parents treated their children differently based on birth order.
According to Quartz, Conger's research revealed that 74 percent of mothers and 70 percent of fathers reported differential treatment toward one child, though they wouldn't reveal which child they favored.
To participate in the study, children had to be living with both parents and had to have a sibling within four years of their age.
Researchers visited the families' homes twice a year for three years, collecting data about how well they got along with each other and with friends, as well as their favorite activities, and ideas on how to solve family conflicts.
The study showed that all children, no matter their birth order, felt as if their parents treated them unfairly.
However, Conger was surprised to find that first-born children seemed unaffected by the findings, which could suggest that they feel they are their parents' preferred child, while the youngest siblings' self-worth seemed to suffer due to differential treatment.
"Our working hypothesis was that older, earlier born children would be more affected by perceptions of differential treatment due to their status as older child—more power due to age and size, more time with parents in the family," Conger told Quartz. "Everyone feels their brother or sister is getting a better deal."
But, siblings, no matter your perceived ranking, there are many reasons to enjoy having those sometimes pesky brothers or sisters.
Conger's longitudinal study was first published in the Journal of Family Psychology in 2005 but has recently resurfaced online, probably because siblings love to poke fun at which one they believe is the preferred child - even though most parents will never own up to favoring one child over another, if they even do at all.