http://www.centerforinquiry.net/blog...er_prediction/
All these gender prediction methods are BS I think. I remember seeing a great chart that showed all the common methods and how none of them really worked.
http://www.sciencebasedmedicine.org/...blers-fallacy/
There are a few rooted in a bit of Science.
Seems like severe morning sickness (requiring hospitalization) can indicate a 50% greater chance of it being a girl.
http://www.ncbi.nlm.nih.gov/pubmed/1...ubmed_RVDocSum
It also seems like Mothers in good physical condition are more likely to produce Males and Mothers in poor physical condition females.
http://www.ncbi.nlm.nih.gov/pubmed/22456881