At 16 weeks of pregnancy can a 3rd ultrasound detect the gender?

At about 20 weeks: Gender is best seen at 18-20 weeks gestation. This is also the time the anatomy scan is usually done. In some cases, the gender can be seen earlier and in still others, we still cannot see it due to the position of the baby and other factors regardless of how far along you are. In general, they can check for gender at 18-20 weeks when they do the anatomy scan.