With DD, I felt like I was having a boy - but I desperately wanted a girl, so I found a couple and did them. They said boy, so I went on a mission. I found seriously 40 different ones online and did them all. They all said boy. Then I found one. One measley one that said girl, and I stopped.
Obviously that one was right and I have a girl.
I didn't do them with DS as they just did my head in lol.