There's nothing wrong with a bit of healthy sibling rivalry.
But when it really comes down to it, if you're older than your siblings, you can call on science to prove your point.
New research from the universities of Mainz and Leipzig suggests that first born children have a higher IQ than their siblings. The scientists reckon this is to do with your parents' undivided attention and having to teach your younger brothers and sisters. Passing on your wisdom probably gives you extra bragging rights, right?
Not really, because your younger siblings are only an estimated 1.5 lower in IQ points per sibling.
And it only happens in families with more than two kids. If you're one of two, you have a six in ten chance of a higher IQ, so your younger relatives still have a strong chance of overtaking you.
Your ego's also come into play - as well as demonstrating a heightened intelligence, older children also displayed an increased perception of their brain power. Meanwhile your younger brother or sister has probably taken a hit from that and tends to see themselves as less bright. Bet you don't feel as smug now.