If your first-born is a girl, then she's destined for great things. For new research says that girls at the top of the pecking grow up to be rich, famous and powerful!
And they point to the likes of J.K. Rowling, Hillary Clinton, Oprah Winfrey and Beyoncé as evidence for the familial phenomenon.
A study by the University of Essex found that that firstborn girls are statistically more likely to be the most highly qualified of all their family – and they are 13 per cent more ambitious then first-born sons.
And while all eldest children are 16 per cent more likely to attend further education than their younger siblings, girls are 4 per cent more likely to have better qualifications.
Lead researcher Feifei Bu said: "There are several possible explanations for the higher attainment and ambition of the eldest.
"It could be that the parents simply devote more time and energy to them – it could be they are actually more intelligent. For me, I tend to lean towards the theory that parental investment is possibly at work here."
The report – Sibling Configurations, Educational Aspiration and Attainment – followed 1,503 sibling groups and 3,532 individuals through the British Household Panel Survey and its successor, Understanding Society.
Even taking into account the parents' education and professional status, the study found firstborn children were still 7 per cent more likely to aspire to stay on in education than younger siblings.
More than half of all Nobel prizewinners and US presidents have been first-borns.
The study looked at gender mix among siblings as well as the size of families – excluding twins and only children – and found there was no evidence that the sex of a second sibling made any difference to their level of aspiration.
But it did discover that leaving an age gap of at least four years between siblings could improve the younger children's levels of educational attainment.
Miss Bu told The Observer: "I would say that the larger the age gap between the children, the better their qualifications will be.
"It is interesting that we observe a distinct first-born advantage in education, even though parents in modern society are more likely to be egalitarian in the way they treat their children."
She added: "I'm the firstborn, of course. That is why I'm doing a PhD."
More on Parentdish:
Why the 'ban bossy' campaign is just silly
Mind the gap! What is the best age gap between children?