Boy vs. Girl

My life drastically changed last May 1st, when I gave birth to a little BOY. I have to say, Nathan and I were both surprised (although apparently my parents KNEW it was going to be a boy). We figured that since we couldn't imagine having a boy, it just had to be a girl....but, my instincts were wrong with Lydia, so I don't know why I assumed I'd know this time.
Luke has not disappointed us in his role as the little man of the family - and at 10 months he is starting to really develop some interesting traits that Lydia never presented. Do these stem from the huge differences between girls and boy / men and women, or are they just the normal, wildly different personalities of two siblings?
Luke loves the train that runs near our house.  For the past month he will stop what he's doing and stare out the window when it goes by; then he does a little tongue between teeth "th"sound. (guess that means choo-choo in baby). Lydia never really cared about the train when we moved here and she was one.
Luke has been super into wheels and his cement truck is his favorite toy EEEVVVEERR - Lydia enjoyed pushing her baby cart at one, but she has just discovered trucks - thanks to Luke.
In general, Luke is just a more destructive, rough, climbing kid than Lydia ever was; it makes us proud, and we say "that's our little BOY."
But is it really a genetic difference? Luke is also much more stubborn than Lydia was with food, toys, etc. He has waited months to do things like sit-up, crawl, or pull-up, and now all the sudden, he is on his way to cruising/walking. Lydia was a very gradual learner. In some ways he almost seems more emotional than Lydia, more set in his ways.....wait a minute! Aren't those female traits? :)
Well, I guess that perhaps many of the differences come from a blend of reasons - none of them bigger than two different personalities and souls, living in two different bodies. I am looking forward to more trucks and camo, and yes - perhaps even some weaponry - in our house some day soon. I love my little boy.