How early can you see gender of fetus?

I knew I was having a boy at 14 weeks.

It's all dependent on how your baby is positioned. My sister wasn't able to tell what her first kid was because she (the fetus) had her legs crossed during the ultrasound. :-)

It's also a lot easier (for obvious reasons) to tell if it's a boy than if it's a girl.

I found out that I was having a boy at 15 weeks!!!! But it just depends on how the baby cooperates with the ultrasound tech.

The earliest a doctor will have a radiologist determine gender is about 12 weeks. Most wait until week 16 through week 20. Determining gender by radiology is not an exact science. A fetus could be in a position where it is difficult to see the genitals. Your radiologist may attempt to coax the fetus into another position where it is more visible. You could also consume something containing sugar, such as juice, (no caffeine!) which will make the fetus somewhat more active. Amniocentesis, if you must have one completed, is fool-proof in determining gender of the fetus through chromosomal testing.