If you have siblings and you’re not the oldest, your happiness is doomed to be at risk.
The first child can do whatever it wants, it can pursue any career or hobby.
The second child is in a tricky position. It wants to be distinct, i.e. different from its sibling, thus it doesn’t want to do whatever the first child does (or even did).
For any following children, there will be even fewer niches open.
Despite having a few way older half siblings and a very young half sister I would consider myself second-born because, for most of my life, I grew up alongside my 4-years older sister. I can definitely see the theory somewhat applying to my life. For example: My sister used to be very big on dancing and even though I really loved it too, I didn’t pursue it because it was her thing and I wanted to have ‘my own thing’. However, as you age you grow out of this ‘sibling-competition’, particularly because you start to actually live your own life rather than keep trying to impress your parents (plus, as adult you can think and reason, which children don’t do all that much 😉 ).
So it’s seems like birth order – i.e. your older siblings – can determine what sort of activities you pursue. Research furthermore shows that there’s even a relationship between birth order and personality (e.g. Sulloway, 1996).
Various research (among others by Sulloway, author of Born To Rebel) report some of the following on the effects of birth order:
These trends can be completely different though in various families, depending on different circumstances, personalities, age gaps, etc. See this article ‘Sibling-order effect‘ for more information.