While we would never dream of picking between our own little angels, we always knew that our siblings were given first choice from that biscuit tin.
Now a research team at The Science of Us has confirmed that 70% of dads and 74% of mums do give preferential treatment to one child over another, although none of the parents interviewed admitted that they would ever fess up to their children about their preference.
Professor Katherine Conger has revealed that the research showed over two thirds of parents do give preferential treatment to one child.
The study took 384 pairs of siblings and interviewed them about how they felt their parents treated them, and if they treated their brothers and sisters any differently.
The team then went on to interview the child's parents and ask them the same questions, to see whether they would agree with the feelings expressed by their offspring.
Unsurprisingly for youngest children, they found that firstborns tended to feel preferred while younger siblings felt they received less positive attention.
Not only that, but youngest siblings said they faced stricter rules - likely because their parents learnt they were too soft the first time round.
This isn't the first study of it's kind to confirm our childhood suspicions.
In 2009 British professors David Lawson and Ruth Mace conducted a study of 14,000 families in Bristol with similar results.
They found that each successive child received 'markedly' less care and attention from their parents than their elder siblings.
In fact, the oldest siblings were even fed better and as a result, were up to 3cm taller and generally had higher IQs - thought to be mainly due to the undivided attention they recieved in the first part of their lives.
Please now feel free to share this fact with your parents until they are forced to admit they owe you a lifetime supply of chocolate biscuits as compensation.