The sexing of your baby (gender determination) can be perofrmed from 16 weeks onwards. It is approximately 90% accurate at 16 weeks and 95% accurate from 20 weeks onwards.
we have been for 2 scans this year and how pleased I am with the service we received. The sonographer is so nice, you never feel rushed and makes you feel very reassured, both times she took the time to explain everything and even when the baby was in an awkward position nothing was to much trouble.