Given the large difference in the returns by month of birth I think there is far too much scatter, not enough sample size, to read anything into this data. Of course you can always write a press article on it to fill up the space.....
You're probably right. It's ridiculous to think anyone's month of birth has anything to do with his investment returns. The sample having 6 times the number of accounts held by men vs. women should mimic a normal population since the stock market attracts a lot more men than women.
You will be surprised to know that in Chinese culture if the person has no or little FORTUNE in his/her birth chart, he/she has little chance to win in gambling, including trading on Wall Street. So it is recommended for them to find another profession.