First-borns are more likely to choose medicine or engineering as a career option and as a consequence earn more money than their siblings, who turn to humanities and academics, finds a study.
The findings, led by researchers from the Max Planck Institute in Munich, Germany, showed that second-borns were 27 percent less likely than the first-borns to apply to medical training programmes.
The difference between first- and third-borns was 54 percent.
The relative probability of second-borns studying arts programmes was 27 percent higher than the first-borns, while the difference was 36 per cent between third-borns and first-borns.
The sibling differences in choice of university programme was not just a consequence of first-borns having better grades in school.
It was more due to parental investment in the early years as it plays a crucial role in shaping the siblings' ability, preferences and ambitions even within the shared environment of the family, the researchers said.
"Our results suggest that parents invest more in earlier-born children than in later-borns and that this shapes sibling differences in ability and ambitions even within the family," said Kieron Barclay, demographer at Max Planck Institute.
"First-borns benefit exclusively from parents' attention as long as they are the only child at home. This gives them a head start," said Mikko Myrskyla, Director at the Institute, in the paper published in the journal Social Forces.
Moreover, in terms of relative probabilities, not only do second-borns differ from first-borns in terms of career choice, the trend towards choosing "less prestigious occupations" increases with every further child.
For example, the probability of second-borns taking up journalism is 16 per cent more likely than first-borns, while third-borns and fourth-borns are, respectively, 40 percent and 60 percent more likely to do so.
This differences in programmes in college could also explain approximately half of the gap in their long-term earnings, the researchers said, in the study involving 146 000 students.