Ok, I don't know what the difference is or what the source is, but the links I posted in my earlier post were all wrong for my first baby, and I found the calendar I used with her that turned out to be right- it wasn't until after I had her from looking at links sent to me by someone else that I even knew there were multiple versions of the calendar out there. Confusing.
But this is the one that was right for me before. With baby #2, it says it's a girl too, and I go for my u/s on Aug 1, so I'll know if it's accurate this time too. Chinese Gender Chart, Gender Determination- iVillage
To the people who said the first one wasn't right for you, does this one give you a different result? Just curious.