Back in 1995 I presented a lecture about gender prediction around the world , I collected more than 1200 ideas under
science and superstitions of baby gender prediction , I presented the lecture at Brunei University lecture hall. The hall was full almost 1000 people attended
many took the lecture and started doing face book and google lectures about the subject . here is one of the good blog that mention some of my ideas.
https://www.chinesegenderchart.info/101-gender-predictors.php
Steve Ramsey