What Week Is Baby Gender REALLY detected?

Toni • Waiting For Her ❣️

I have an ultrasound coming up on Valentine’s Day, I’ll be 1 day away from 19 weeks exactly . So I’ll be 18 weeks and 7 days. I am really hoping to get the gender, but I’m worried I might have to wait longer because friends have been telling me they had to wait until about 23-24 weeks. And call me impatient , but I don’t want to wait that long. I’ve heard of people getting the gender as early as 12. What is this based off of?