I remember it being the other way around, but like you said; it's just for fun so people probably just made their own up as they went along :)
Didn't work for said girl and chinese calender said GIRL too... I got TJ or a boy
i heard circle for girl and line for boy
LOL @ Cindie. I think its circle for a girl and line for a boy.
Line for boy circle for girl.
My family does the same thing just slightly different. It has never been wrong for us.