"The more siblings you had growing up probably makes you more likely to be a dog person."

That doesn't really work for me and my brother but my sisters all love dogs - maybe its your position in the sibling hierachy that affects your love of dogs - if you're lower down in the food chain maybe you tend to band together with those family (or pack) members who are more on your level - not that I'm saying my sisters are dogs of course - er...right...Oi'll get mi coat...