All my various calculations turned out to be wrong. Even here a woman, Natalia, predicted a boy for me, but no — the ultrasound confirmed a girl ) Now I'm readjusting ))
Once the pregnancy reaches about 18–20 weeks you go for an ultrasound and they tell you the baby's sex. There is no method to predict the sex in advance. Any method you find is pure luck — exactly a 50% chance.
I also think there's nothing except ultrasound, although I don't trust ultrasounds, of course you want to believe in some method ) At 17 weeks they said boy, at 20 weeks girl) we don't know who to believe)