Ramzi theory of gender prediction???

Deven • Pregnant with baby #1 after 9 months of trying! Due May 2, 2016 ❤️
How does this theory work? The baby appears to be in the middle of my ultrasound picture but I don't know if that matters or if it goes based on which side the yolk sac is on. The yolk sac is on the left side of the baby. What do you guys think? Boy or girl? This is a 7 week 1 day vaginal ultrasound