Does anyone know for sure
.....19-20 weeks is the norm, but of course bubs must be co-operating musnt they ???
My 3rd pregnancy i was desperate to find out the sex. But bubs had legs firmly shut....sonsographer really couldnt have cared less , but i was devastated. So i booked in for another ultrasound (at my expense, not thru medicare which only allows you 1 scan during 18-22 wks).....

So whilst you may have the timing right, baby might have other ideas, just warning you.