That's so interesting!!
I have 1 sister and 2 brothers that are married and having children. Up to now the girls of our family have only had daughters and the boys of our family have only had boys. SIL is pregnant right now and we are waiting to see if she's having a girl, (probably will because she could care less what she has). If she's carrying a girl it will break the pattern, if she's having a boy it will stay.
I would love to have a boy and we *might* try for a boy in a year or two, but I'm soooo afraid of having another girl, which is not a good place to be if I'm going to risk it through swaying!!