quite a few girls from the December 2010 DCC well now
PR did it awhile back and we compared the % of it being right from what the mom thought it would be, the dad, the chinese calender and tested it with the US... the intellegender was the least accurate and most times wrong! :/ hopefully it works for u though... i never used it so i don't know... there's also this cabagge test too! hehe but all this is always fun to try!