gender predictions for fun?

Shannon
Has anyone tried any gender predictions? I went on printrest and tried a few. 
•Ramzi Ultrasound theory 
•Wives tales like: morning sickness or no? Acne or clear skin? Food cravings 
• ring test ( put your ring on a string and see if it swings in a circle or back and forth
• Chinese calander. 
• heart rate above or below 140 
• mayan calander 
And they all have said girl. Has anyone had any luck with these?