Honestly, I've never believed in any of these old wives' tales! In Russia they have lots of them too, including this one, about the shape of your bump. Sometimes people can be quite annoying, telling you all the way through that they 'know' who you're having just because they go by these myths.
My belly's shape is kinda hard to tell: not really pointy, but at the same time it's not perfectly round either. According to the scan we did last week, I'm going to have a girl.
I have a friend whose belly was always pointy during her 3 pregnancies and folks continually said she was with boys, yet, all of her pregnancies turned out to be girls.
I think human body (especially, when it comes to women's health and childbearing) is so complicated, with so many unsolved mysteries, that there simply cannot be any definitive answers or recipes...