My parents had 4 kids but in two sets. First set four years apart. Second set born starting seven years later and six years apart. So I was one girl out of three boys and my eldest brother is 11 years older than me. He went on to get a PhD in Physics and ultimately became a venture capitalist in the science world, ie he was brilliant. Youngest (my baby brother) was very spoiled and still hadn't figured out how to make a living when he died at 31. It is interesting that with my identical grand-twins that one is clearly the boss. I think there are probably many overarching things that affect children besides birth order - divorce, trauma, development during fetal stage etc. For example, I find it hard to relate to other women sometimes and I think it has to do with never having a sister. I am more comfortable with males.